Electronic Device and Program

ABSTRACT

An electronic device with a high security level is provided. The electronic device includes a control portion, a memory portion, and a display portion. The display portion has a function of displaying a first icon and a function of obtaining first fingerprint data in a display region of the first icon. The memory portion has a function of retaining second fingerprint data. The control portion has a function of comparing the first fingerprint data with the second fingerprint data; a function of executing first processing associated with the first icon in the case where the first fingerprint data and the second fingerprint data match; and a function of executing second processing in the case where the first fingerprint data and the second fingerprint data do not match.

TECHNICAL FIELD

One embodiment of the present invention relates to an electronic device.One embodiment of the present invention relates to an authenticationmethod. One embodiment of the present invention relates to a displaydevice. One embodiment of the present invention relates to a program.

Note that one embodiment of the present invention is not limited to theabove technical field. Examples of the technical field of one embodimentof the present invention include a semiconductor device, a displaydevice, a light-emitting device, a power storage device, a memorydevice, an electronic device, a lighting device, an input device (e.g.,a touch sensor), an input/output device (e.g., a touch panel), a methodfor driving any of them, and a method for manufacturing any of them.

BACKGROUND ART

In recent years, information terminal devices, for example, mobilephones such as smartphones, tablet information terminals, and laptop PCs(personal computers) have been widely used. Such information terminaldevices often include personal information or the like, and thus variousauthentication technologies for preventing abuse have been developed.

For example, Patent Document 1 discloses an electronic device includinga fingerprint sensor in a push button switch portion.

REFERENCE Patent Document

-   [Patent Document 1] United States Published Patent Application No.    2014/0056493

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

An object of one embodiment of the present invention is to provide anelectronic device with a high security level. Another object is toprovide an electronic device capable of suitably inhibiting unauthorizeduse. Another object is to provide a novel electronic device.

Note that the description of these objects does not preclude theexistence of other objects. One embodiment of the present invention doesnot need to achieve all of these objects. Other objects can be derivedfrom the description of the specification, the drawings, and the claims.

Means for Solving the Problems

One embodiment of the present invention is a program for making anelectronic device, which includes a display portion having a function ofobtaining fingerprint data and a function of displaying a first icon, acontrol portion, and a memory portion, execute the step of obtainingfirst fingerprint data in a display region of the first icon in thedisplay portion; the step of comparing, in the control portion, thefirst fingerprint data with second fingerprint data included in thememory portion; the step of executing first processing associated withthe first icon in the control portion in the case where the firstfingerprint data and the second fingerprint data match; and the step ofexecuting second processing in the control portion in the case where thefirst fingerprint data and the second fingerprint data do not match.

The display portion preferably has a function of detecting a touchmotion. Furthermore, the program is preferably a program for making theelectronic device execute the step of detecting a touch motion in thedisplay region of the first icon.

The display portion preferably has a function of displaying a secondicon. Furthermore, the program may be a program for making theelectronic device execute the step of obtaining third fingerprint datain a display region of the second icon in the display portion; the stepof comparing, in the control portion, the third fingerprint data withfourth fingerprint data included in the memory portion; the step ofexecuting third processing associated with the second icon in thecontrol portion in the case where the third fingerprint data and thefourth fingerprint data match; and the step of executing fourthprocessing in the control portion in the case where the thirdfingerprint data and the fourth fingerprint data do not match.Alternatively, the program is preferably a program for further makingthe electronic device execute the step of detecting a touch motion in adisplay region of a second icon and the step of executing thirdprocessing associated with the second icon in the control portion.

One embodiment of the present invention is a program for making anelectronic device, which includes a display portion having a function ofobtaining fingerprint data and a function of displaying a first icon, acontrol portion, and a memory portion, execute the step of obtaining aplurality of pieces of first fingerprint data in a display region of thefirst icon in the display portion; the step of comparing, in the controlportion, each of the plurality of pieces of first fingerprint data witha plurality of pieces of second fingerprint data included in the memoryportion; the step of executing first processing associated with thefirst icon in the control portion in the case where each of theplurality of pieces of first fingerprint data and any of the pluralityof pieces of second fingerprint data match; and the step of executingsecond processing in the control portion in the case where at least oneof the plurality of pieces of first fingerprint data does not match withany of the plurality of pieces of second fingerprint data.

The display portion preferably has a function of detecting a touchmotion. Furthermore, the program is preferably a program for making theelectronic device execute the step of detecting a touch motion in thedisplay region of the first icon.

One embodiment of the present invention is a non-transitory computerreadable recording medium storing any of the programs.

One embodiment of the present invention is an electronic deviceincluding a control portion, a memory portion, and a display portion.The display portion has a function of displaying a first icon and afunction of obtaining first fingerprint data in a display region of thefirst icon. The memory portion has a function of retaining secondfingerprint data. The control portion has a function of comparing thefirst fingerprint data with the second fingerprint data; a function ofexecuting first processing associated with the first icon in the casewhere the first fingerprint data and the second fingerprint data match;and a function of executing second processing in the case where thefirst fingerprint data and the second fingerprint data do not match.

In the above electronic device, it is preferable that the displayportion further have a function of detecting a touch motion in thedisplay region of the first icon.

In the above electronic device, it is preferable that the displayportion further have a function of displaying a second icon and afunction of obtaining third fingerprint data in a display region of thesecond icon; the memory portion further have a function of retainingfourth fingerprint data; and the control portion further have a functionof comparing the third fingerprint data with the fourth fingerprintdata, a function of executing third processing associated with thesecond icon in the case where the third fingerprint data and the fourthfingerprint data match, and a function of executing fourth processing inthe case where the third fingerprint data and the fourth fingerprintdata do not match.

Alternatively, in the above electronic device, it is preferable that thedisplay portion further have a function of displaying a second icon anda function of detecting a touch motion in a display region of the secondicon, and the control portion further have a function of executing thirdprocessing associated with the second icon in the case where the displayportion detects the touch motion on the second icon.

One embodiment of the present invention is an electronic deviceincluding a control portion, a memory portion, and a display portion.The display portion has a function of displaying a first icon and afunction of obtaining a plurality of pieces of first fingerprint data ina display region of the first icon. The memory portion has a function ofretaining a plurality of pieces of second fingerprint data. The controlportion has a function of comparing each of the plurality of pieces offirst fingerprint data with the plurality of pieces of secondfingerprint data; a function of executing first processing associatedwith the first icon in the case where each of the plurality of pieces offirst fingerprint data and any of the plurality of pieces of secondfingerprint data match; and a function of executing second processing inthe case where at least one of the plurality of pieces of firstfingerprint data does not match with any of the plurality of pieces ofsecond fingerprint data.

In each of the above programs and electronic devices, the secondprocessing is preferably processing to lock data associated with thefirst icon.

Alternatively, in each of the above programs and electronic devices, itis preferable that the first processing be processing to display dataassociated with the first icon on the display portion and the secondprocessing be processing to display data different from the dataassociated with the first icon on the display portion.

Effect of the Invention

According to one embodiment of the present invention, an electronicdevice with a high security level can be provided. Alternatively, anelectronic device capable of suitably inhibiting unauthorized use can beprovided. Alternatively, a novel electronic device can be provided.

Note that the description of these effects does not preclude theexistence of other effects. One embodiment of the present invention doesnot necessarily have all of these effects. Other effects can be derivedfrom the description of the specification, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an electronic device of one embodiment ofthe present invention.

FIG. 2 is a flow chart of an operation of an electronic device of oneembodiment of the present invention.

FIG. 3A to FIG. 3C are diagrams illustrating a structure example of anelectronic device of one embodiment of the present invention and anoperation method example thereof.

FIG. 4A to FIG. 4C are diagrams illustrating a structure example of anelectronic device of one embodiment of the present invention and anoperation method example thereof.

FIG. 5A to FIG. 5C are diagrams illustrating a structure example of anelectronic device of one embodiment of the present invention and anoperation method example thereof.

FIG. 6A to FIG. 6C are diagrams illustrating a structure example of anelectronic device of one embodiment of the present invention and anoperation method example thereof.

FIG. 7A to FIG. 7E are diagrams illustrating a structure example of anelectronic device of one embodiment of the present invention and anoperation method example thereof.

FIG. 8 is a diagram illustrating a structure example of an electronicdevice of one embodiment of the present invention.

FIG. 9 is a block diagram of an electronic device of one embodiment ofthe present invention.

FIG. 10A to FIG. 10D and FIG. 10F are cross-sectional views eachillustrating an example of a display device. FIG. 10E and FIG. 10G arediagrams each illustrating an example of an image captured by thedisplay device. FIG. 10H and FIG. 10J to FIG. 10L are top views eachillustrating an example of a pixel.

FIG. 11A to FIG. 11G are top views illustrating examples of pixels.

FIG. 12A and FIG. 12B are cross-sectional views each illustrating anexample of a display device.

FIG. 13A and FIG. 13B are cross-sectional views illustrating an exampleof a display device.

FIG. 14A to FIG. 14C are cross-sectional views illustrating examples ofdisplay devices.

FIG. 15A is a cross-sectional view illustrating an example of a displaydevice. FIG. 15B and FIG. 15C are diagrams each illustrating an exampleof a top-surface layout of a resin layer.

FIG. 16 is a perspective view illustrating an example of a displaydevice.

FIG. 17 is a cross-sectional view illustrating an example of a displaydevice.

FIG. 18 is a cross-sectional view illustrating an example of a displaydevice.

FIG. 19A is a cross-sectional view illustrating an example of a displaydevice. FIG. 19B is a cross-sectional view illustrating an example of atransistor.

FIG. 20A and FIG. 20B are circuit diagrams each illustrating an exampleof a pixel circuit.

FIG. 21A and FIG. 21B are diagrams illustrating an example of anelectronic device.

FIG. 22A to FIG. 22D are diagrams illustrating examples of electronicdevices.

FIG. 23A to FIG. 23F are diagrams illustrating examples of electronicdevices.

MODE FOR CARRYING OUT THE INVENTION

Embodiments are described in detail with reference to the drawings.However, the present invention is not limited to the followingdescription, and it is readily appreciated by those skilled in the artthat modes and details can be modified in various ways without departingfrom the spirit and the scope of the present invention. Thus, thepresent invention should not be construed as being limited to thedescription in the following embodiments.

Note that in structures of the invention described below, the sameportions or portions having similar functions are denoted by the samereference numerals in different drawings, and a description thereof isnot repeated. Furthermore, the same hatch pattern is used for theportions having similar functions, and the portions are not especiallydenoted by reference numerals in some cases.

The position, size, range, or the like of each component illustrated indrawings does not represent the actual position, size, range, or thelike in some cases for easy understanding. Therefore, the disclosedinvention is not necessarily limited to the position, size, range, orthe like disclosed in the drawings.

Note that the term “film” and the term “layer” can be interchanged witheach other depending on the case or circumstances. For example, the term“conductive layer” can be replaced with the term “conductive film”. Asanother example, the term “insulating film” can be replaced with theterm “insulating layer”.

Embodiment 1

In this embodiment, an electronic device of one embodiment of thepresent invention and an operation method of the electronic device aredescribed.

Note that in the drawings attached to this specification, the blockdiagram in which components are classified according to their functionsand shown as independent blocks is illustrated; however, it is difficultto separate actual components completely according to their functions,and one component may be related to a plurality of functions or aplurality of components may achieve one function.

An electronic device of one embodiment of the present invention has afunction of displaying an icon on a display portion, a function ofobtaining fingerprint data in a display region of the icon, and afunction of executing user authentication processing using thefingerprint data. For example, when a user accesses data with a highsecurity level, fingerprint data can be obtained in a display region ofan icon associated with the data and authentication processing can beexecuted. Thus, even in the case where another person unlocks theelectronic device by an unauthorized method or logs in systems by anunauthorized method, access to data with a high security level can beprevented. Furthermore, unauthorized execution of processing requiring ahigh security level, such as payment, e-mail transmission, or deletionof file can be prevented.

For example, in the case of an electronic device that requires apassword to access data associated with an icon, a malicious user whoobtains the password improperly might use the data associated with theicon in an unauthorized manner. In addition, the malicious user mightnotice that the data associated with the icon is important because ofrequirement of the password. Moreover, in the case of an electronicdevice that displays a message saying failure of fingerprintauthentication when fingerprint authentication is failed at the time ofuser's touch on the icon, the user might notice that the userauthentication processing is executed and that the data associated withthe icon is important. Note that in this specification and the like, totouch an icon means to touch a display region of the icon in a displayportion.

The electronic device of one embodiment of the present inventionrequires fingerprint authentication when a user accesses data associatedwith an icon; therefore, unauthorized access to the data by a malicioususer can be prevented. Furthermore, the electronic device of oneembodiment of the present invention requires fingerprint authenticationand displays different pieces of data depending on the result of thefingerprint authentication, when a user accesses data associated with anicon. Therefore, the user can be less likely to notice that the userauthentication processing is executed and that the data associated withthe icon is important.

The electronic device of one embodiment of the present invention mayrequire fingerprint authentication of a plurality of people when thedata associated with the icon is accessed. In this manner, a higherlevel of security can be ensured as compared to an electronic devicerequiring one fingerprint or an electronic device requiring a password.

More specific structure examples of the electronic device of oneembodiment of the present invention are described below with referenceto drawings.

[Structure Example of Electronic Device]

FIG. 1 illustrates a block diagram of an electronic device 10 of oneembodiment of the present invention. The electronic device 10 includes acontrol portion 11, a memory portion 12, and a display portion 13. Theelectronic device 10 can be used as an information terminal device, forexample.

The display portion 13 has a function of displaying an image, a functionof detecting a touch motion, and a function of obtaining fingerprintdata. That is, the display portion 13 has a function of outputtingpositional data of a finger touching a screen to the control portion 11and a function of capturing an image of a fingerprint of the finger tooutput the image data as fingerprint data to the control portion. Forexample, a display device described in detail in Embodiment 2 can beused for the display portion 13. Note that, as the touch motion, contactis given and approach may be included. The touch motion can also bereferred to as an input motion by touch or touch input.

It is preferable that detecting a touch motion and obtaining fingerprintdata be performed in any portion on the display portion 13.

The display portion 13 preferably has a function of detecting aplurality of touch motions and a function of obtaining fingerprint dataof a plurality of fingers.

The memory portion 12 has a function of retaining user's fingerprintdata registered in advance. The memory portion 12 can output thefingerprint data to the control portion 11 in accordance with therequest from the control portion 11.

The memory portion 12 preferably retains fingerprint data on all thefingers of a user used in operating the screen. For example, two piecesof fingerprint data on user's right and left index fingers can beretained. In addition to them, it is preferable that one or more piecesof fingerprint data on a middle finger, a ring finger, a little finger,and a thumb be capable of being retained. Fingerprint data on aplurality of users may be retained.

The control portion 11 has a function of comparing the fingerprint datainput from the display portion 13 with the fingerprint data registeredin advance (the function may also be referred to as a fingerprintauthentication function). Moreover, the control portion 11 can executeprocessing in accordance with the result of the fingerprintauthentication. In the case where the control portion 11 determines thatthese pieces of fingerprint data match, the control portion 11 executesfirst processing associated with the touched icon. Examples of the firstprocessing include opening a file or a folder, starting software,application, or the like, deleting data, making a purchase, and sendingan e-mail. Furthermore, the control portion 11 can make the displayportion 13 display data on the basis of these processings. For example,the control portion 11 makes the display portion 13 display first dataassociated with the touched icon. In contrast, in the case where thecontrol portion 11 determines that these two pieces of fingerprint datado not match, the control portion 11 executes second processingdifferent from the first processing associated with the icon. Examplesof the second processing include locking data, a system, or the like;displaying a message of authentication failure (error message); openinga file, a folder, or the like different from that in the firstprocessing; starting software, application, or the like different fromthat in the first processing; protecting data; and canceling a purchase,e-mail transmission, or the like. Furthermore, the control portion 11can make the display portion 13 display data on the basis of theseprocessings. For example, the control portion 11 locks the first dataassociated with the icon or displays the second data different from thefirst data associated with the icon.

Examples of a fingerprint authentication method executed by the controlportion 11 include a method evaluating the degree of similarity betweentwo images compared, e.g., a template matching method or a patternmatching method. For example, when the value of the degree of similarityis higher than or equal to a predetermined value, two pieces offingerprint data can be determined to match. Alternatively, fingerprintauthentication processing may be executed by inference using machinelearning. At this time, the fingerprint authentication processing ispreferably executed by inference using a neural network, in particular.

The control portion 11 can function as, for example, a centralprocessing unit (CPU). The control portion 11 interprets and executesinstructions from various programs with the use of a processor toprocess various kinds of data and control programs. Programs that mightbe executed by the processor may be stored in a memory region of theprocessor or may be stored in the memory portion 12.

[Operation Example of Electronic Device 10]

An operation example of the electronic device 10 is described below.FIG. 2 is a flow chart showing the operation of the electronic device10. The flow chart shown in FIG. 2 includes Step S1 to Step S5.

First, in Step S1, the display portion 13 performs detection of a touchmotion. In the case where the display portion 13 detects a touch motionon an icon with which fingerprint authentication is performed (YES), theoperation proceeds to Step S2. When a touch motion on the icon is notperformed (NO), the operation is on standby until a touch motion isperformed (the operation proceeds to Step S1 again).

In Step S2, fingerprint data is obtained in a display region of the iconin the display portion 13.

In Step S3, the control portion 11 compares the fingerprint dataobtained in Step S2 with fingerprint data registered in advance. In thecase where the authentication succeeds (the control portion 11determines that the two pieces of fingerprint data match) (YES), theoperation proceeds to Step S4. In the case where the authenticationfails (the control portion 11 determines that the two pieces offingerprint data do not match) (NO), the operation proceeds to Step S5.

In Step S4, the control portion 11 executes processing (the firstprocessing) associated with the icon that is displayed on the displayportion 13 and touched by the user. As the processing associated withthe icon displayed on the display portion 13, processing of displayingdata associated with the icon or the like can be given.

In Step S5, the control portion 11 executes processing (the secondprocessing) that is different from the processing associated with theicon that is displayed on the display portion 13 and touched by theuser. Examples of the second processing include processing of lockingthe data associated with the icon and processing of displaying seconddata different from the data associated with the icon.

The above is the description of the flow chart shown in FIG. 2 .

Note that a processing method, an operation method, a driving method, adisplay method, or the like that is executed by the electronic device ofone embodiment of the present invention might be described as a program,for example. For example, a program in which the processing method, theoperation method, the driving method, the display method, or the likethat is executed by the above-exemplified electronic device 10 or thelike is written can be stored in a non-transitory computer readablerecording medium (also simply referred to as a recording medium or astorage medium) and can be read out and executed by an arithmetic deviceor the like included in the control portion 11 of the electronic device10. That is, a program that makes hardware execute the above-exemplifiedoperation method or the like and a non-transitory computer readablerecording medium storing the program are embodiments of the presentinvention.

As the non-transitory computer readable recording medium, a hard discdrive (HDD), a solid state drive (SSD), a flash memory, a Blu-ray Disc,a DVD, or the like can be used.

Specific Example

A specific example of the electronic device of one embodiment of thepresent invention is described below.

FIG. 3A schematically illustrates an electronic device 30 and a finger21. The electronic device 30 includes a display portion 31. Theelectronic device 30 is a portable information terminal devicefunctioning as a smartphone, for example. The finger 21 is touching anicon 32 displayed on the display portion 31. At this time, fingerprintauthentication of the finger 21 is performed.

FIG. 3B illustrates a fingerprint 22 obtained from the finger 21 andfingerprint data 23 registered in the electronic device 30 in advance.In this case, the fingerprint 22 and the fingerprint data 23 match, sothat processing (the first processing) associated with the icon 32touched by the finger 21 is executed.

FIG. 3C illustrates a fingerprint 22X obtained from the finger 21 andthe fingerprint data 23 registered in the electronic device 30 inadvance. In this case, the fingerprint 22X and the fingerprint data 23do not match, so that the second processing different from theprocessing associated with the icon 32 touched by the finger 21 isexecuted.

FIG. 4A illustrates the state where the finger 21 is touching the icon32 displayed on the electronic device 30. In this case, the fingerprint22X of the finger 21 and the fingerprint data 23 registered in theelectronic device 30 in advance do not match, so that the above secondprocessing is executed (FIG. 4B). Here, an example is illustrated inwhich the data associated with the icon 32 is locked. At this time, data33 (Information Locked) indicating that the data associated with theicon 32 is locked may be displayed on the display portion 31 asillustrated in FIG. 4C.

In FIG. 5A, the fingerprint 22 obtained from the finger 21 touching theicon 32 and the fingerprint data 23 registered in advance match, so thatthe above first processing is executed (FIG. 5B). Here, an example isillustrated in which the data associated with the icon 32 is displayed.As illustrated in FIG. 5C, first data 35 (File A) is displayed on thedisplay portion 31.

In contrast, in FIG. 6A and FIG. 6B, the fingerprint 22X obtained fromthe finger 21 touching the icon 32 and the fingerprint data 23registered in advance do not match. Thus, the above second processing isexecuted. FIG. 6C illustrates an example in which second data 36 (FileB) is displayed.

When locking of data is displayed as the second processing asillustrated in FIG. 4C, the user might notice that the userauthentication processing is executed and furthermore, that the dataassociated with the icon is important. In FIG. 6C, File B, which isdifferent from File A that is the first data 35, is displayed as thesecond data 36. Therefore, the user can be less likely to notice thatthe user authentication processing is performed and furthermore, thatthe data associated with the icon is important.

FIG. 7 illustrates an example of the case where authentication of aplurality of fingerprints is needed to execute the processing associatedwith the icon 32. First, as illustrated in FIG. 7A, fingerprintauthentication starts by a touch on the icon 32 with the finger 21. Thefingerprint 22 is obtained from the finger 21; when the fingerprint 22is determined to match with the fingerprint data 23 registered inadvance (see FIG. 7D), the operation proceeds to a step ofauthenticating the next fingerprint. Next, as illustrated in FIG. 7B,fingerprint authentication is performed by a touch on the icon 32 with afinger 24. When a fingerprint 25 obtained from the finger 24 isdetermined to match with fingerprint data 26 registered in advance (seeFIG. 7E), the processing associated with the icon 32 is executed. Asillustrated in FIG. 7C, data 34 (Access Accepted) indicating the successof the fingerprint authentication may be displayed on the displayportion 31.

Note that after the fingerprint 22 is obtained from the finger 21 andthe fingerprint 25 is obtained from the finger 24, the comparison of thefingerprint 22 with the fingerprint data 23 and the comparison of thefingerprint 25 with the fingerprint data 26 may be performed.Alternatively, after the fingerprint 22 is obtained from the finger 21,the obtainment of the fingerprint 25 and the comparison of thefingerprint 22 with the fingerprint data 23 may be performed inparallel.

FIG. 8 illustrates another example of the case where authentication of aplurality of fingerprints is needed to execute the processing associatedwith the icon 32.

An electronic device 40 illustrated in FIG. 8 functions as a laptoppersonal computer.

The electronic device 40 includes a display portion 41, an input portion42, a plurality of input keys 43, a housing 44, a housing 45, a hingeportion 46, and the like. The housing 44 is provided with the displayportion 41. The housing 45 is provided with the input portion 42 and theinput keys 43. The housing 44 and the housing 45 are joined together bythe hinge portion 46.

In FIG. 8 , the finger 21 and the finger 24 are touching the icon 32displayed on the display portion 41. The display portion 41 has afunction of capturing images of fingerprints of a plurality of fingerstouching the icon 32 and outputting the image data as fingerprint datato a control portion (not illustrated). Accordingly, the control portioncan recognize that both the finger 21 and the finger 24 are touching theicon 32 and can perform fingerprint authentication of the finger 21 andthe finger 24. Then, when the fingerprint authentication of the finger21 and the finger 24 succeeds, the processing associated with the icon32 is executed.

Note that fingerprint data to be authenticated may differ depending onicons. For example, when a finger having a first fingerprint touches afirst icon, processing associated with the first icon is executed. Incontrast, when a finger having a fingerprint other than the firstfingerprint touches the first icon, the processing associated with thefirst icon is not executed. When a finger having a second fingerprinttouches a second icon, processing associated with the second icon isexecuted. In contrast, when a finger having a fingerprint other than thesecond fingerprint touches the second icon, the processing associatedwith the second icon is not executed. In this manner, in an electronicdevice shared by a plurality of people, a file that can be opened onlywith a fingerprint of a user A, a folder that can be opened only with afingerprint of a user B, or the like can be created as appropriate, forexample.

Among icons displayed on the electronic device, the number of icons forperforming fingerprint authentication may be one or more. For example,fingerprint authentication is performed with an icon associated withdata or processing with a high security level, while fingerprintauthentication is not necessarily performed with an icon associated withdata or processing with a relatively low security level. On a touch ofan icon not for performing fingerprint authentication, processingassociated with the icon is executed regardless of fingerprints offingers touching the icon.

Modification Example

Although the example in which the display portion 13 has a function ofdetecting a touch motion is described above, the present invention isnot limited thereto. As in an electronic device 10A illustrated in FIG.9 , a detection portion 14 having a function of detecting a touch motionmay be included in addition to the display portion 13.

The display portion 13 has a function of displaying an image and afunction of obtaining fingerprint data. Specifically, the displayportion 13 has a function of displaying an icon and obtainingfingerprint data in a display region of the icon. The detection portion14 has a function of detecting a touch motion. A capacitive touch sensoror the like can be used in the detection portion 14.

This embodiment can be combined with the other embodiments asappropriate. In this specification, in the case where a plurality ofstructure examples are shown in one embodiment, the structure examplescan be combined as appropriate.

Embodiment 2

In this embodiment, display devices of embodiments of the presentinvention are described with reference to FIG. 10 to FIG. 19 .

The display device of this embodiment can be favorably used in thedisplay portion of the electronic device described in Embodiment 1.

The display portion of the display device of one embodiment of thepresent invention has a function of displaying an image with the use ofa light-emitting element (also referred to as a light-emitting device).Furthermore, the display portion also has one or both of an imagecapturing function and a sensing function.

The display device of one embodiment of the present invention includes alight-receiving element (also referred to as a light-receiving device)and a light-emitting element. Alternatively, the display device of oneembodiment of the present invention includes a light-emitting andlight-receiving element (also referred to as a light-emitting andlight-receiving device) and a light-emitting element.

First, a display device including a light-receiving element and alight-emitting element is described.

The display device of one embodiment of the present invention includes alight-receiving element and a light-emitting element in a displayportion. In the display device of one embodiment of the presentinvention, the light-emitting elements are arranged in a matrix in thedisplay portion, and an image can be displayed on the display portion.Furthermore, the light-receiving elements are arranged in a matrix inthe display portion, and the display portion has one or both of an imagecapturing function and a sensing function. The display portion can beused as an image sensor or a touch sensor. That is, by detecting lightwith the display portion, an image can be captured and a touch motion ofan object (e.g., a finger or a stylus) can be detected. Furthermore, inthe display device of one embodiment of the present invention, thelight-emitting elements can be used as a light source of the sensor.Accordingly, a light-receiving portion and a light source do not need tobe provided separately from the display device; hence, the number ofcomponents of an electronic device can be reduced.

In the display device of one embodiment of the present invention, whenan object reflects (or scatters) light emitted from the light-emittingelement included in the display portion, the light-receiving element candetect the reflected light (or the scattered light); thus, imagecapturing and touch motion detection are possible even in a dark place.

The display device of one embodiment of the present invention has afunction of displaying an image with the use of a light-emittingelement. That is, the light-emitting element functions as a displayelement (also referred to as a display device).

As the light-emitting element, an EL element (also referred to as an ELdevice) such as an OLED (Organic Light Emitting Diode) or a QLED(Quantum-dot Light Emitting Diode) is preferably used. As alight-emitting substance contained in the EL element, a substanceexhibiting fluorescence (a fluorescent material), a substance exhibitingphosphorescence (a phosphorescent material), an inorganic compound (suchas a quantum dot material), a substance exhibiting thermally activateddelayed fluorescence (a thermally activated delayed fluorescence (TADF)material), or the like can be given. Alternatively, an LED (LightEmitting Diode) such as a micro-LED can be used as the light-emittingelement.

The display device of one embodiment of the present invention has afunction of detecting light with the use of a light-receiving element.

When the light-receiving element is used as an image sensor, the displaydevice can capture an image using the light-receiving element. Forexample, the display device of this embodiment can be used as a scanner.

For example, data on biological information of a fingerprint, a palmprint, or the like can be obtained with the use of the image sensor.That is, a biometric authentication sensor can be incorporated in thedisplay device. When the display device incorporates a biometricauthentication sensor, the number of components of an electronic devicecan be reduced as compared to the case where a biometric authenticationsensor is provided separately from the display device; thus, the sizeand weight of the electronic device can be reduced.

When the light-receiving element is used as the touch sensor, thedisplay device can detect a touch motion of an object with the use ofthe light-receiving element.

As the light-receiving element, a pn photodiode or a pin photodiode canbe used, for example. The light-receiving element functions as aphotoelectric conversion element (also referred to as a photoelectricconversion device) that detects light entering the light-receivingelement and generates charge. The amount of charge generated from thelight-receiving element depends on the amount of light entering thelight-receiving element.

It is particularly preferable to use an organic photodiode including alayer containing an organic compound as the light-receiving element. Anorganic photodiode, which is easily made thin, lightweight, and large inarea and has a high degree of freedom for shape and design, can be usedin a variety of display devices.

In one embodiment of the present invention, organic EL elements (alsoreferred to as organic EL devices) are used as the light-emittingelements, and organic photodiodes are used as the light-receivingelements. The organic EL elements and the organic photodiodes can beformed over one substrate. Thus, the organic photodiodes can beincorporated in the display device including the organic EL elements.

If all the layers of the organic EL elements and the organic photodiodesare formed separately, the number of deposition steps becomes extremelylarge. Since a large number of layers of the organic photodiodes canhave structures in common with the organic EL elements, concurrentlydepositing the layers that can have a common structure can inhibit anincrease in the number of deposition steps.

For example, one of a pair of electrodes (a common electrode) can be alayer shared by the light-receiving element and the light-emittingelement. For example, at least one of a hole-injection layer, ahole-transport layer, an electron-transport layer, and anelectron-injection layer is preferably a layer shared by thelight-receiving element and the light-emitting element. As anotherexample, the light-receiving element and the light-emitting element canhave the same structure except that the light-receiving element includesan active layer and the light-emitting element includes a light-emittinglayer. In other words, the light-receiving element can be manufacturedby only replacing the light-emitting layer of the light-emitting elementwith an active layer. When the light-receiving element and thelight-emitting element include common layers in such a manner, thenumber of deposition steps and the number of masks can be reduced,thereby reducing the number of manufacturing steps and the manufacturingcost of the display device. Furthermore, the display device includingthe light-receiving element can be manufactured using an existingmanufacturing apparatus and an existing manufacturing method for thedisplay device.

Note that a layer shared by the light-receiving element and thelight-emitting element might have functions different in thelight-receiving element and the light-emitting element. In thisspecification, the name of a component is based on its function in thelight-emitting element. For example, a hole-injection layer functions asa hole-injection layer in the light-emitting element and functions as ahole-transport layer in the light-receiving element. Similarly, anelectron-injection layer functions as an electron-injection layer in thelight-emitting element and functions as an electron-transport layer inthe light-receiving element. Note that a layer shared by thelight-receiving element and the light-emitting element may have the samefunctions in the light-receiving element and the light-emitting element.A hole-transport layer functions as a hole-transport layer in both ofthe light-emitting element and the light-receiving element, and anelectron-transport layer functions as an electron-transport layer inboth of the light-emitting element and the light-receiving element.

Next, a display device including a light-emitting and light-receivingelement and a light-emitting element is described.

In the display device of one embodiment of the present invention, asubpixel exhibiting any color includes a light-emitting andlight-receiving element instead of a light-emitting element, andsubpixels exhibiting the other colors each include a light-emittingelement. The light-emitting and light-receiving element has both afunction of emitting light (a light-emitting function) and a function ofreceiving light (a light-receiving function). For example, in the casewhere a pixel includes three subpixels of a red subpixel, a greensubpixel, and a blue subpixel, at least one of the subpixels includes alight-emitting and light-receiving element, and the other subpixels eachinclude a light-emitting element. Thus, the display portion of thedisplay device of one embodiment of the present invention has a functionof displaying an image using both a light-emitting and light-receivingelement and a light-emitting element.

The light-emitting and light-receiving element functions as both alight-emitting element and a light-receiving element, whereby the pixelcan have a light-receiving function without an increase in the number ofsubpixels included in the pixel. Thus, the display portion of thedisplay device can be provided with one or both of an image capturingfunction and a sensing function while keeping the aperture ratio of thepixel (aperture ratio of each subpixel) and the resolution of thedisplay device. Accordingly, in the display device of one embodiment ofthe present invention, the aperture ratio of the pixel can be moreincreased and the resolution can be increased more easily than in adisplay device provided with a subpixel including a light-receivingelement separately from a subpixel including a light-emitting element.

In the display portion of the display device of one embodiment of thepresent invention, the light-emitting and light-receiving elements andthe light-emitting elements are arranged in a matrix, and an image canbe displayed on the display portion. The display portion can be used asan image sensor or a touch sensor. In the display device of oneembodiment of the present invention, the light-emitting elements can beused as a light source of the sensor. Accordingly, a light-receivingportion and a light source do not need to be provided separately fromthe display device; hence, the number of components of an electronicdevice can be reduced.

In the display device of one embodiment of the present invention, whenan object reflects (or scatters) light emitted from the light-emittingelement included in the display portion, the light-emitting andlight-receiving element can detect the reflected light (or the scatteredlight); thus, image capturing and touch motion detection are possibleeven in a dark place.

The light-emitting and light-receiving element can be manufactured bycombining an organic EL element and an organic photodiode. For example,by adding an active layer of an organic photodiode to a layeredstructure of an organic EL element, the light-emitting andlight-receiving element can be manufactured. Furthermore, in thelight-emitting and light-receiving element formed of a combination of anorganic EL element and an organic photodiode, concurrently depositinglayers that can be shared with the organic EL element can inhibit anincrease in the number of deposition steps.

For example, one of a pair of electrodes (a common electrode) can be alayer shared by the light-emitting and light-receiving element and thelight-emitting element. For example, at least one of a hole-injectionlayer, a hole-transport layer, an electron-transport layer, and anelectron-injection layer is preferably a layer shared by thelight-emitting and light-receiving element and the light-emittingelement. As another example, the light-emitting and light-receivingelement and the light-emitting element can have the same structureexcept for the presence or absence of an active layer of thelight-receiving element. In other words, the light-emitting andlight-receiving element can be manufactured by only adding the activelayer of the light-receiving element to the light-emitting element. Whenthe light-emitting and light-receiving element and the light-emittingelement include common layers in such a manner, the number of depositionsteps and the number of masks can be reduced, thereby reducing thenumber of manufacturing steps and the manufacturing cost of the displaydevice. Furthermore, the display device including the light-emitting andlight-receiving element can be manufactured using an existingmanufacturing apparatus and an existing manufacturing method for thedisplay device.

Note that a layer included in the light-emitting and light-receivingelement might have a different function between the case where thelight-emitting and light-receiving element functions as alight-receiving element and the case where the light-emitting andlight-receiving element functions as a light-emitting element. In thisspecification, the name of a component is based on its function in thecase where the light-emitting and light-receiving element functions as alight-emitting element. For example, a hole-injection layer functions asa hole-injection layer in the case where the light-emitting andlight-receiving element functions as a light-emitting element, andfunctions as a hole-transport layer in the case where the light-emittingand light-receiving element functions as a light-receiving element.Similarly, an electron-injection layer functions as anelectron-injection layer in the case where the light-emitting andlight-receiving element functions as a light-emitting element, andfunctions as an electron-transport layer in the case where thelight-emitting and light-receiving element functions as alight-receiving element. A layer included in the light-emitting andlight-receiving element may have the same function in both the casewhere the light-emitting and light-receiving element functions as alight-receiving element and the case where the light-emitting andlight-receiving element functions as a light-emitting element. Thehole-transport layer functions as a hole-transport layer in the casewhere the light-emitting and light-receiving element functions as eithera light-emitting element or a light-receiving element, and theelectron-transport layer functions as an electron-transport layer in thecase where the light-emitting and light-receiving element functions aseither a light-emitting element or a light-receiving element.

The display device of this embodiment has a function of displaying animage with the use of a light-emitting element and a light-emitting andlight-receiving element. That is, the light-emitting element and thelight-emitting and light-receiving element function as display elements.

The display device of this embodiment has a function of detecting lightwith the use of a light-emitting and light-receiving element. Thelight-emitting and light-receiving element can detect light having ashorter wavelength than light emitted from the light-emitting andlight-receiving element itself.

When the light-emitting and light-receiving element is used as an imagesensor, the display device of this embodiment can capture an image usingthe light-emitting and light-receiving element. For example, the displaydevice of this embodiment can be used as a scanner.

When the light-emitting and light-receiving element is used as the touchsensor, the display device of this embodiment can detect a touch motionof an object with the use of the light-emitting and light-receivingelement.

The light-emitting and light-receiving element functions as aphotoelectric conversion element that detects light entering thelight-emitting and light-receiving element and generates charge. Theamount of charge generated from the light-emitting and light-receivingelement depends on the amount of light entering the light-emitting andlight-receiving element.

The light-emitting and light-receiving element can be manufactured byadding an active layer of the light-receiving element to theabove-described structure of the light-emitting element.

A pn or pin photodiode structure can be applied to the light-emittingand light-receiving element, for example.

It is particularly preferable to use, for the light-emitting andlight-receiving element, an active layer of an organic photodiodeincluding a layer containing an organic compound. An organic photodiode,which is easily made thin, lightweight, and large in area and has a highdegree of freedom for shape and design, can be used in a variety ofdisplay devices.

The display device of one embodiment of the present invention isspecifically described below with reference to drawings.

[Display Device]

FIG. 10A to FIG. 10D and FIG. 10F illustrate cross-sectional views ofdisplay devices of embodiments of the present invention.

A display device 200A illustrated in FIG. 10A includes a layer 203including a light-receiving element, a functional layer 205, and a layer207 including a light-emitting element between a substrate 201 and asubstrate 209.

In the display device 200A, red (R) light, green (G) light, and blue (B)light are emitted from the layer 207 including a light-emitting element.

The light-receiving element included in the layer 203 including alight-receiving element can detect light that enters from the outside ofthe display device 200A.

A display device 200B illustrated in FIG. 10B includes a layer 204including a light-emitting and light-receiving element, the functionallayer 205, and the layer 207 including a light-emitting element betweenthe substrate 201 and the substrate 209.

In the display device 200B, green (G) light and blue (B) light areemitted from the layer 207 including a light-emitting element, and red(R) light is emitted from the layer 204 including a light-emitting andlight-receiving element. In the display device of one embodiment of thepresent invention, the color of light emitted from the layer 204including a light-emitting and light-receiving element is not limited tored. Furthermore, the color of light emitted from the layer 207including a light-emitting element is not limited to the combination ofgreen and blue.

The light-emitting and light-receiving element included in the layer 204including a light-emitting and light-receiving element can detect lightthat enters from the outside of the display device 200B. Thelight-emitting and light-receiving element can detect one or both ofgreen (G) light and blue (B) light, for example.

The functional layer 205 includes a circuit for driving thelight-receiving element or the light-emitting and light-receivingelement and a circuit for driving the light-emitting element. A switch,a transistor, a capacitor, a resistor, a wiring, a terminal, and thelike can be provided in the functional layer 205. Note that in the casewhere the light-emitting element and the light-receiving element aredriven by a passive-matrix method, a structure not provided with aswitch or a transistor may be employed.

The display device of one embodiment of the present invention may have afunction of detecting an object such as a finger that is touching thedisplay device (a function of a touch panel). For example, after lightemitted from the light-emitting element in the layer 207 including alight-emitting element is reflected by a finger 202 that is touching thedisplay device 200A as illustrated in FIG. 10C, the light-receivingelement in the layer 203 including a light-receiving element detects thereflected light. Thus, the touch of the finger 202 on the display device200A can be detected. Furthermore, in the display device 200B, afterlight emitted from the light-emitting element in the layer 207 includinga light-emitting element is reflected by a finger that is touching thedisplay device 200B, the light-emitting and light-receiving element inthe layer 204 including a light-emitting and light-receiving element candetect the reflected light. Although a case where light emitted from thelight-emitting element is reflected by an object is described below asan example, light might be scattered by an object.

The display device of one embodiment of the present invention may have afunction of detecting an object that is close to (but is not touching)the display device as illustrated in FIG. 10D or capturing an image ofsuch an object.

The display device of one embodiment of the present invention may have afunction of detecting a fingerprint of the finger 202. FIG. 10Eillustrates a diagram of an image captured by the display device of oneembodiment of the present invention. In an image-capturing range 263 inFIG. 10E, the outline of the finger 202 is indicated by a dashed lineand the outline of a contact portion 261 is indicated by a dashed-dottedline. In the contact portion 261, a high-contrast image of a fingerprint262 can be captured owing to a difference in the amount of lightentering the light-receiving element (or the light-emitting andlight-receiving element).

The display device of one embodiment of the present invention can alsofunction as a pen tablet. FIG. 10F illustrates a state in which a tip ofa stylus 208 slides in a direction indicated by a dashed arrow while thetip of the stylus 208 touches the substrate 209.

As illustrated in FIG. 10F, when the scattered light scattered by thecontact surface between the tip of the stylus 208 and the substrate 209enters the light-receiving element (or the light-emitting andlight-receiving element) that is positioned in a portion overlappingwith the contact surface, the position of the tip of the stylus 208 canbe detected with high accuracy.

FIG. 10G illustrates an example of a path 266 of the stylus 208 that isdetected by the display device of one embodiment of the presentinvention. The display device of one embodiment of the present inventioncan detect the position of an object to be detected, such as the stylus208, with high position accuracy, so that high-definition drawing can beperformed using a drawing application or the like. Unlike the case ofusing a capacitive touch sensor, an electromagnetic induction touch pen,or the like, the display device can detect even the position of a highlyinsulating object to be detected, the material of a tip portion of thestylus 208 is not limited, and a variety of writing materials (e.g., abrush, a glass pen, a quill pen, and the like) can be used.

[Pixel]

The display device of one embodiment of the present invention includes aplurality of pixels arranged in a matrix. One pixel includes a pluralityof subpixels. One subpixel includes one light-emitting element, onelight-emitting and light-receiving element, or one light-receivingelement.

The plurality of pixels each include one or more of a subpixel includinga light-emitting element, a subpixel including a light-receivingelement, and a subpixel including a light-emitting and light-receivingelement.

For example, the pixel includes a plurality of (e.g., three or four)subpixels each including a light-emitting element and one subpixelincluding a light-receiving element.

Note that the light-receiving element may be provided in all the pixelsor may be provided in some of the pixels. In addition, one pixel mayinclude a plurality of light-receiving elements. One light-receivingelement may be provided across a plurality of pixels. The resolution ofthe light-receiving element may be different from the resolution of thelight-emitting element.

In the case where the pixel includes three subpixels each including alight-emitting element, as the three subpixels, subpixels of threecolors of R, G, and B, subpixels of three colors of yellow (Y), cyan(C), and magenta (M), and the like can be given. In the case where thepixel includes four subpixels each including a light-emitting element,as the four subpixels, subpixels of four colors of R, G, B, and white(W), subpixels of four colors of R, G, B, and Y, and the like can begiven.

FIG. 10H, FIG. 10J, FIG. 10K, and FIG. 10L illustrate examples of apixel which includes a plurality of subpixels each including alight-emitting element and includes one subpixel including alight-receiving element. Note that the arrangement of subpixels is notlimited to the illustrated order in this embodiment. For example, thepositions of a subpixel (B) and a subpixel (G) may be reversed.

The pixels illustrated in FIG. 10H, FIG. 10J, and FIG. 10K each includea subpixel (PD) having a light-receiving function, a subpixel (R) thatexhibits red light, a subpixel (G) that exhibits green light, and asubpixel (B) that exhibits blue light.

Matrix arrangement is applied to the pixel illustrated in FIG. 10H, andstripe arrangement is applied to the pixel illustrated in FIG. 10J. FIG.10K illustrates an example in which the subpixel (R) that exhibits redlight, the subpixel (G) that exhibits green light, and the subpixel (B)that exhibits blue light are arranged laterally in one row and thesubpixel (PD) having a light-receiving function is arranged thereunder.In other words, in FIG. 10K, the subpixel (R), the subpixel (G), and thesubpixel (B) are arranged in the same row, which is different from therow in which the subpixel (PD) is provided.

The pixel illustrated in FIG. 10L includes a subpixel (X) that exhibitslight of a color other than R, G, and B, in addition to the componentsof the pixel illustrated in FIG. 10K. The light of a color other than R,G, and B can be white (W) light, yellow (Y) light, cyan (C) light,magenta (M) light, infrared light (IR), or the like. In the case wherethe subpixel (X) exhibits infrared light, the subpixel (PD) having alight-receiving function preferably has a function of detecting infraredlight. The subpixel (PD) having a light-receiving function may have afunction of detecting both visible light and infrared light. Thewavelength of light detected by the light-receiving element can bedetermined depending on the application of a sensor.

Alternatively, for example, the pixel includes a plurality of subpixelseach including a light-emitting element and one subpixel including alight-emitting and light-receiving element.

The display device including the light-emitting and light-receivingelement has no need to change the pixel arrangement when incorporating alight-receiving function into pixels; thus, a display portion can beprovided with one or both of an image capturing function and a sensingfunction without reductions in aperture ratio and resolution.

Note that the light-emitting and light-receiving element may be providedin all the pixels or may be provided in some of the pixels. In addition,one pixel may include a plurality of light-emitting and light-receivingelements.

FIG. 11A to FIG. 11D illustrate examples of a pixel which includes aplurality of subpixels each including a light-emitting element andincludes one subpixel including a light-emitting and light-receivingelement.

A pixel illustrated in FIG. 11A employs stripe arrangement and includesa subpixel (RPD) that exhibits red light and has a light-receivingfunction, a subpixel (G) that exhibits green light, and a subpixel (B)that exhibits blue light. In a display device including a pixel composedof three subpixels of R, G, and B, a light-emitting element used in theR subpixel can be replaced with a light-emitting and light-receivingelement, so that the display device can have a light-receiving functionin the pixel.

A pixel illustrated in FIG. 11B includes a subpixel (RPD) that exhibitsred light and has a light-receiving function, a subpixel (G) thatexhibits green light, and a subpixel (B) that exhibits blue light. Thesubpixel (RPD) is provided in a column different from a column where thesubpixel (G) and the subpixel (B) are positioned. The subpixel (G) andthe subpixel (B) are alternately arranged in the same column; one isprovided in an odd-numbered row and the other is provided in aneven-numbered row. The color of the subpixel positioned in a columndifferent from the column where the subpixels of the other colors arepositioned is not limited to red (R) and may be green (G) or blue (B).

A pixel illustrated in FIG. 11C employs matrix arrangement and includesa subpixel (RPD) that exhibits red light and has a light-receivingfunction, a subpixel (G) that exhibits green light, a subpixel (B) thatexhibits blue light, and a subpixel (X) that exhibits light of a colorother than R, G, and B. Also in a display device including a pixelcomposed of four subpixels of R, G, B, and X, a light-emitting elementused in the R subpixel can be replaced with a light-emitting andlight-receiving element, so that the display device can have alight-receiving function in the pixel.

FIG. 11D illustrates two pixels, each of which is composed of threesubpixels surrounded by dotted lines. The pixels illustrated in FIG. 11Deach include a subpixel (RPD) that exhibits red light and has alight-receiving function, a subpixel (G) that exhibits green light, anda subpixel (B) that exhibits blue light. In the pixel on the left inFIG. 11D, the subpixel (G) is positioned in the same row as the subpixel(RPD), and the subpixel (B) is positioned in the same column as thesubpixel (RPD). In the pixel on the right in FIG. 11D, the subpixel (G)is positioned in the same row as the subpixel (RPD), and the subpixel(B) is positioned in the same column as the subpixel (G). In everyodd-numbered row and every even-numbered row of the pixel layoutillustrated in FIG. 11D, the subpixel (RPD), the subpixel (G), and thesubpixel (B) are repeatedly arranged. In addition, subpixels ofdifferent colors are arranged in the odd-numbered row and theeven-numbered row in every column.

FIG. 11E illustrates four pixels which employ pentile arrangement;adjacent two pixels each have a different combination of two subpixelsthat exhibit light of different colors. Note that the shapes of thesubpixels illustrated in FIG. 11E each indicate a top-surface shape ofthe light-emitting element or the light-emitting and light-receivingelement included in the subpixel. FIG. 11F is a modification example ofthe pixel arrangement of FIG. 11E.

The upper-left pixel and the lower-right pixel in FIG. 11E each includea subpixel (RPD) that exhibits red light and has a light-receivingfunction and a subpixel (G) that exhibits green light. The lower-leftpixel and the upper-right pixel in FIG. 11E each include a subpixel (G)that exhibits green light and a subpixel (B) that exhibits blue light.

The upper-left pixel and the lower-right pixel in FIG. 11F each includea subpixel (RPD) that exhibits red light and has a light-receivingfunction and a subpixel (G) that exhibits green light. The lower-leftpixel and the upper-right pixel in FIG. 11F each include a subpixel(RPD) that exhibits red light and has a light-receiving function and asubpixel (B) that exhibits blue light.

In FIG. 11E, the subpixel (G) that exhibits green light is provided ineach pixel. Meanwhile, in FIG. 11F, the subpixel (RPD) that exhibits redlight and has a light-receiving function is provided in each pixel. Thestructure illustrated in FIG. 11F achieves higher-resolution imagecapturing than the structure illustrated in FIG. 11E because of having asubpixel having a light-receiving function in each pixel. Thus, theaccuracy of biometric authentication can be increased, for example.

The top-surface shapes of the light-emitting elements and thelight-emitting and light-receiving elements are not particularly limitedand can be a circular shape, an elliptical shape, a polygonal shape, apolygonal shape with rounded corners, or the like. The top-surface shapeof the light-emitting elements included in the subpixels (G) is acircular in the example in FIG. 11E and square in the example in FIG.11F. The top-surface shape of the light-emitting elements and thelight-emitting and light-receiving elements may vary depending on thecolor thereof, or the light-emitting elements and the light-emitting andlight-receiving elements of some colors or every color may have the sametop-surface shape.

The aperture ratio of subpixels may vary depending on the color of thesubpixels, or may be the same among the subpixels of some colors orevery color. For example, the aperture ratio of a subpixel of a colorprovided in each pixel (the subpixel (G) in FIG. 11E, and the subpixel(RPD) in FIG. 11F) may be made lower than those of subpixels of theother colors.

FIG. 11G is a modification example of the pixel arrangement of FIG. 11F.Specifically, the structure of FIG. 11G is obtained by rotating thestructure of FIG. 11F by 45°. Although one pixel is regarded as beingformed of two subpixels in FIG. 11F, one pixel can be regarded as beingformed of four subpixels as illustrated in FIG. 11G.

In the description with reference to FIG. 11G, one pixel is regarded asbeing formed of four subpixels surrounded by dotted lines. A pixelincludes two subpixels (RPD), one subpixel (G), and one subpixel (B).The pixel including a plurality of subpixels each having alight-receiving function allows high-resolution image capturing.Accordingly, the accuracy of biometric authentication can be increased.For example, the resolution of image capturing can be the square root of2 times the resolution of display.

A display device which employs the structure illustrated in FIG. 11F orFIG. 11G includes p (p is an integer greater than or equal to 2) firstlight-emitting elements, q (q is an integer greater than or equal to 2)second light-emitting elements, and r (r is an integer greater than pand q) light-emitting and light-receiving elements. As for p and r, r=2pis satisfied. As for p, q, and r, r=p+q is satisfied. Either the firstlight-emitting elements or the second light-emitting elements emit greenlight, and the other light-emitting elements emit blue light. Thelight-emitting and light-receiving elements emit red light and have alight-receiving function.

In the case where a touch motion is detected with the light-emitting andlight-receiving elements, for example, it is preferable that lightemitted from a light source be hard for a user to recognize. Since bluelight has low visibility than green light, light-emitting elements thatemit blue light are preferably used as a light source. Accordingly, thelight-emitting and light-receiving elements preferably have a functionof receiving blue light.

As described above, the display device of this embodiment can employ anyof various types of pixel arrangements.

[Device Structure]

Next, detailed structures of the light-emitting element, thelight-receiving element, and the light-emitting and light-receivingelement which can be used in the display device of one embodiment of thepresent invention are described.

The display device of one embodiment of the present invention can haveany of the following structures: a top-emission structure in which lightis emitted in a direction opposite to the substrate where thelight-emitting element is formed, a bottom-emission structure in whichlight is emitted toward the substrate where the light-emitting elementis formed, and a dual-emission structure in which light is emittedtoward both surfaces.

In this embodiment, a top-emission display device is described as anexample.

In this specification and the like, unless otherwise specified, indescribing a structure including a plurality of components (e.g.,light-emitting elements or light-emitting layers), alphabets are notadded when a common part for the components is described. For example,when a common part of a light-emitting layer 283R, a light-emittinglayer 283G, and the like is described, the light-emitting layers aresimply referred to as a light-emitting layer 283, in some cases.

A display device 280A illustrated in FIG. 12A includes a light-receivingelement 270PD, a light-emitting element 270R that emits red (R) light, alight-emitting element 270G that emits green (G) light, and alight-emitting element 270B that emits blue (B) light.

Each of the light-emitting elements includes a pixel electrode 271, ahole-injection layer 281, a hole-transport layer 282, a light-emittinglayer, an electron-transport layer 284, an electron-injection layer 285,and a common electrode 275 which are stacked in this order. Thelight-emitting element 270R includes the light-emitting layer 283R, thelight-emitting element 270G includes the light-emitting layer 283G, andthe light-emitting element 270B includes a light-emitting layer 283B.The light-emitting layer 283R includes a light-emitting substance thatemits red light, the light-emitting layer 283G includes a light-emittingsubstance that emits green light, and the light-emitting layer 283Bincludes a light-emitting substance that emits blue light.

The light-emitting elements are electroluminescent elements that emitlight to the common electrode 275 side by voltage application betweenthe pixel electrodes 271 and the common electrode 275.

The light-receiving element 270PD includes the pixel electrode 271, thehole-injection layer 281, the hole-transport layer 282, an active layer273, the electron-transport layer 284, the electron-injection layer 285,and the common electrode 275 which are stacked in this order.

The light-receiving element 270PD is a photoelectric conversion elementthat receives light entering from the outside of the display device 280Aand converts it into an electric signal.

In the description made in this embodiment, the pixel electrode 271functions as an anode and the common electrode 275 functions as acathode in both of the light-emitting element and the light-receivingelement. In other words, when the light-receiving element is driven byapplication of reverse bias between the pixel electrode 271 and thecommon electrode 275, light entering the light-receiving element can bedetected and charge can be generated and extracted as current.

In the display device of this embodiment, an organic compound is usedfor the active layer 273 of the light-receiving element 270PD. In thelight-receiving element 270PD, the layers other than the active layer273 can have structures in common with the layers in the light-emittingelements. Therefore, the light-receiving element 270PD can be formedconcurrently with the formation of the light-emitting elements only byadding a step of depositing the active layer 273 in the manufacturingprocess of the light-emitting elements. The light-emitting elements andthe light-receiving element 270PD can be formed over one substrate.Accordingly, the light-receiving element 270PD can be incorporated intothe display device without a significant increase in the number ofmanufacturing steps.

The display device 280A is an example in which the light-receivingelement 270PD and the light-emitting elements have a common structureexcept that the active layer 273 of the light-receiving element 270PDand the light-emitting layers 283 of the light-emitting elements areseparately formed. Note that the structures of the light-receivingelement 270PD and the light-emitting elements are not limited thereto.The light-receiving element 270PD and the light-emitting elements mayinclude separately formed layers other than the active layer 273 and thelight-emitting layers 283. The light-receiving element 270PD and thelight-emitting elements preferably include at least one layer used incommon (common layer). Thus, the light-receiving element 270PD can beincorporated into the display device without a significant increase inthe number of manufacturing steps.

A conductive film that transmits visible light is used as the electrodethrough which light is extracted, which is either the pixel electrode271 or the common electrode 275. A conductive film that reflects visiblelight is preferably used as the electrode through which light is notextracted.

The light-emitting elements included in the display device of thisembodiment preferably employs a micro optical resonator (microcavity)structure. Thus, one of the pair of electrodes of the light-emittingelements is preferably an electrode having properties of transmittingand reflecting visible light (a semi-transmissive and semi-reflectiveelectrode), and the other is preferably an electrode having a propertyof reflecting visible light (a reflective electrode). When thelight-emitting elements have a microcavity structure, light obtainedfrom the light-emitting layers can be resonated between both of theelectrodes, whereby light emitted from the light-emitting elements canbe intensified.

Note that the semi-transmissive and semi-reflective electrode can have astacked-layer structure of a reflective electrode and an electrodehaving a property of transmitting visible light (also referred to as atransparent electrode).

The light transmittance of the transparent electrode is greater than orequal to 40%. For example, an electrode having a visible light (lightwith a wavelength greater than or equal to 400 nm and less than 750 nm)transmittance higher than or equal to 40% is preferably used in thelight-emitting elements. The semi-transmissive and semi-reflectiveelectrode has a visible light reflectance of higher than or equal to 10%and lower than or equal to 95%, preferably higher than or equal to 30%and lower than or equal to 80%. The reflective electrode has a visiblelight reflectance of higher than or equal to 40% and lower than or equalto 100%, preferably higher than or equal to 70% and lower than or equalto 100%. These electrodes preferably have a resistivity less than orequal to 1×10⁻² Ωcm. Note that in the case where any of thelight-emitting elements emits near-infrared light (light with awavelength greater than or equal to 750 nm and less than or equal to1300 nm), the near-infrared light transmittance and reflectance of theseelectrodes preferably satisfy the above-described numerical ranges ofthe visible light transmittance and reflectance.

The light-emitting element includes at least the light-emitting layer283. The light-emitting element may further include, as a layer otherthan the light-emitting layer 283, a layer containing a substance with ahigh hole-injection property, a substance with a high hole-transportproperty, a hole-blocking material, a substance with a highelectron-transport property, a substance with a high electron-injectionproperty, a substance with a bipolar property (a substance with a highelectron- and hole-transport property), or the like.

For example, the light-emitting elements and the light-receiving elementcan share at least one of the hole-injection layer, the hole-transportlayer, the electron-transport layer, and the electron-injection layer.Furthermore, at least one of the hole-injection layer, thehole-transport layer, the electron-transport layer, and theelectron-injection layer can be separately formed for the light-emittingelements and the light-receiving element.

The hole-injection layer is a layer injecting holes from an anode to thehole-transport layer, and a layer containing a material with a highhole-injection property. As the material with a high hole-injectionproperty, an aromatic amine compound and a composite material containinga hole-transport material and an acceptor material (electron-acceptingmaterial) can be used.

In the light-emitting element, the hole-transport layer is a layertransporting holes, which are injected from the anode by thehole-injection layer, to the light-emitting layer. In thelight-receiving element, the hole-transport layer is a layertransporting holes, which are generated in the active layer on the basisof incident light, to the anode. The hole-transport layer is a layercontaining a hole-transport material. As the hole-transport material, asubstance having a hole mobility greater than or equal to 10⁻⁶ cm²/Vs ispreferable. Note that other substances can also be used as long as theyhave a property of transporting more holes than electrons. As thehole-transport material, materials having a high hole-transportproperty, such as a π-electron rich heteroaromatic compound (e.g., acarbazole derivative, a thiophene derivative, and a furan derivative)and an aromatic amine (a compound having an aromatic amine skeleton),are preferable.

In the light-emitting element, the electron-transport layer is a layertransporting electrons, which are injected from the cathode by theelectron-injection layer, to the light-emitting layer. In thelight-receiving element, the electron-transport layer is a layertransporting electrons, which are generated in the active layer on thebasis of incident light, to the cathode. The electron-transport layer isa layer containing an electron-transport material. As theelectron-transport material, a substance having an electron mobilitygreater than or equal to 1×10⁻⁶ cm²/Vs is preferable. Note that othersubstances can also be used as long as they have a property oftransporting more electrons than holes. As the electron-transportmaterial, it is possible to use a material having a highelectron-transport property, such as a metal complex having a quinolineskeleton, a metal complex having a benzoquinoline skeleton, a metalcomplex having an oxazole skeleton, a metal complex having a thiazoleskeleton, an oxadiazole derivative, a triazole derivative, an imidazolederivative, an oxazole derivative, a thiazole derivative, aphenanthroline derivative, a quinoline derivative having a quinolineligand, a benzoquinoline derivative, a quinoxaline derivative, adibenzoquinoxaline derivative, a pyridine derivative, a bipyridinederivative, a pyrimidine derivative, or a π-electron deficientheteroaromatic compound such as a nitrogen-containing heteroaromaticcompound.

The electron-injection layer is a layer injecting electrons from acathode to the electron-transport layer, and a layer containing amaterial with a high electron-injection property. As the material with ahigh electron-injection property, an alkali metal, an alkaline earthmetal, or a compound thereof can be used. As the material with a highelectron-injection property, a composite material containing anelectron-transport material and a donor material (electron-donatingmaterial) can also be used.

The light-emitting layer 283 is a layer containing a light-emittingsubstance. The light-emitting layer 283 can contain one or more kinds oflight-emitting substances. As the light-emitting substance, a substancethat exhibits an emission color of blue, purple, bluish purple, green,yellowish green, yellow, orange, red, or the like is appropriately used.As the light-emitting substance, a substance that emits near-infraredlight can also be used.

Examples of the light-emitting substance include a fluorescent material,a phosphorescent material, a TADF material, and a quantum dot material.

Examples of the fluorescent material include a pyrene derivative, ananthracene derivative, a triphenylene derivative, a fluorene derivative,a carbazole derivative, a dibenzothiophene derivative, a dibenzofuranderivative, a dibenzoquinoxaline derivative, a quinoxaline derivative, apyridine derivative, a pyrimidine derivative, a phenanthrene derivative,and a naphthalene derivative.

Examples of the phosphorescent material include an organometalliccomplex (particularly an iridium complex) having a 4H-triazole skeleton,a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, apyrazine skeleton, or a pyridine skeleton; an organometallic complex(particularly an iridium complex) having a phenylpyridine derivativeincluding an electron-withdrawing group as a ligand; a platinum complex;and a rare earth metal complex.

The light-emitting layer 283 may contain one or more kinds of organiccompounds (e.g., a host material and an assist material) in addition tothe light-emitting substance (a guest material). As the one or morekinds of organic compounds, one or both of the hole-transport materialand the electron-transport material can be used. As the one or morekinds of organic compounds, a bipolar material or a TADF material may beused.

The light-emitting layer 283 preferably includes a phosphorescentmaterial and a combination of a hole-transport material and anelectron-transport material that easily forms an exciplex. With such astructure, light emission can be efficiently obtained by ExTET(Exciplex—Triplet Energy Transfer), which is energy transfer from anexciplex to a light-emitting substance (a phosphorescent material). Whena combination of materials is selected so as to form an exciplex thatexhibits light emission whose wavelength overlaps with the wavelength ofa lowest-energy-side absorption band of the light-emitting substance,energy can be transferred smoothly and light emission can be obtainedefficiently. With this structure, high efficiency, low-voltage driving,and a long lifetime of the light-emitting element can be achieved at thesame time.

In the combination of materials for forming an exciplex, the HOMO level(the highest occupied molecular orbital level) of the hole-transportmaterial is preferably higher than or equal to the HOMO level of theelectron-transport material. The LUMO level (the lowest unoccupiedmolecular orbital level) of the hole-transport material is preferablyhigher than or equal to the LUMO level of the electron-transportmaterial. Note that the LUMO levels and the HOMO levels of the materialscan be derived from the electrochemical characteristics (the reductionpotentials and the oxidation potentials) of the materials that aremeasured by cyclic voltammetry (CV).

Note that the formation of an exciplex can be confirmed by a phenomenonin which the emission spectrum of a mixed film in which thehole-transport material and the electron-transport material are mixed isshifted to the longer wavelength side than the emission spectrum of eachof the materials (or has another peak on the longer wavelength side),observed by comparison of the emission spectra of the hole-transportmaterial, the electron-transport material, and the mixed film of thesematerials, for example. Alternatively, the formation of an exciplex canbe confirmed by a difference in transient response, such as a phenomenonin which the transient photoluminescence (PL) lifetime of the mixed filmhas longer lifetime components or has a larger proportion of delayedcomponents than that of each of the materials, observed by comparison ofthe transient PL of the hole-transport material, the transient PL of theelectron-transport material, and the transient PL of the mixed film ofthese materials. The transient PL can be rephrased as transientelectroluminescence (EL). That is, the formation of an exciplex can alsobe confirmed by a difference in transient response observed bycomparison of the transient EL of the hole-transport material, thetransient EL of the electron-transport material, and the transient EL ofthe mixed film of these materials.

The active layer 273 includes a semiconductor. Examples of thesemiconductor include an inorganic semiconductor such as silicon and anorganic semiconductor including an organic compound. This embodimentshows an example in which an organic semiconductor is used as thesemiconductor included in the active layer 273. The use of an organicsemiconductor is preferable because the light-emitting layer 283 and theactive layer 273 can be formed by the same method (e.g., a vacuumevaporation method) and thus the same manufacturing apparatus can beused.

Examples of an n-type semiconductor material contained in the activelayer 273 are electron-accepting organic semiconductor materials such asfullerene (e.g., C₆₀ and C₇₀) and a fullerene derivative. Fullerene hasa soccer ball-like shape, which is energetically stable. Both the HOMOlevel and the LUMO level of fullerene are deep (low). Having a deep LUMOlevel, fullerene has an extremely high electron-accepting property(acceptor property). When π-electron conjugation (resonance) spreads ina plane as in benzene, the electron-donating property (donor property)usually increases. Although π-electrons widely spread in fullerenehaving a spherical shape, its electron-accepting property is high. Thehigh electron-accepting property efficiently causes rapid chargeseparation and is useful for a light-receiving element. Both C₆₀ and C₇₀have a wide absorption band in the visible light region, and C₇₀ isespecially preferable because of having a larger π-electron conjugationsystem and a wider absorption band in the long wavelength region thanC₆₀.

Examples of the n-type semiconductor material include a metal complexhaving a quinoline skeleton, a metal complex having a benzoquinolineskeleton, a metal complex having an oxazole skeleton, a metal complexhaving a thiazole skeleton, an oxadiazole derivative, a triazolederivative, an imidazole derivative, an oxazole derivative, a thiazolederivative, a phenanthroline derivative, a quinoline derivative, abenzoquinoline derivative, a quinoxaline derivative, adibenzoquinoxaline derivative, a pyridine derivative, a bipyridinederivative, a pyrimidine derivative, a naphthalene derivative, ananthracene derivative, a coumarin derivative, a rhodamine derivative, atriazine derivative, and a quinone derivative.

Examples of a p-type semiconductor material contained in the activelayer 273 include electron-donating organic semiconductor materials suchas copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene(DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), andquinacridone.

Examples of a p-type semiconductor material include a carbazolederivative, a thiophene derivative, a furan derivative, and a compoundhaving an aromatic amine skeleton. Other examples of the p-typesemiconductor material include a naphthalene derivative, an anthracenederivative, a pyrene derivative, a triphenylene derivative, a fluorenederivative, a pyrrole derivative, a benzofuran derivative, abenzothiophene derivative, an indole derivative, a dibenzofuranderivative, a dibenzothiophene derivative, an indolocarbazolederivative, a porphyrin derivative, a phthalocyanine derivative, anaphthalocyanine derivative, a quinacridone derivative, a polyphenylenevinylene derivative, a polyparaphenylene derivative, a polyfluorenederivative, a polyvinylcarbazole derivative, and a polythiophenederivative.

The HOMO level of the electron-donating organic semiconductor materialis preferably shallower (higher) than the HOMO level of theelectron-accepting organic semiconductor material. The LUMO level of theelectron-donating organic semiconductor material is preferably shallower(higher) than the LUMO level of the electron-accepting organicsemiconductor material.

Fullerene having a spherical shape is preferably used as theelectron-accepting organic semiconductor material, and an organicsemiconductor material having a substantially planar shape is preferablyused as the electron-donating organic semiconductor material. Moleculesof similar shapes tend to aggregate, and aggregated molecules of similarkinds, which have molecular orbital energy levels close to each other,can increase the carrier-transport property.

For example, the active layer 273 is preferably formed by co-evaporationof an n-type semiconductor and a p-type semiconductor.

Either a low molecular compound or a high molecular compound can be usedfor the light-emitting element and the light-receiving element, and aninorganic compound may also be contained. Each of the layers included inthe light-emitting element and the light-receiving element can be formedby an evaporation method (including a vacuum evaporation method), atransfer method, a printing method, an inkjet method, a coating method,or the like.

A display device 280B illustrated in FIG. 12B is different from thedisplay device 280A in that the light-receiving element 270PD and thelight-emitting element 270R have the same structure.

The light-receiving element 270PD and the light-emitting element 270Rshare the active layer 273 and the light-emitting layer 283R.

Here, it is preferable that the light-receiving element 270PD have astructure in common with the light-emitting element that emits lightwith a wavelength longer than that of the light desired to be detected.For example, the light-receiving element 270PD having a structure inwhich blue light is detected can have a structure which is similar tothat of one or both of the light-emitting element 270R and thelight-emitting element 270G. For example, the light-receiving element270PD having a structure in which green light is detected can have astructure similar to that of the light-emitting element 270R.

When the light-receiving element 270PD and the light-emitting element270R have a common structure, the number of deposition steps and thenumber of masks can be smaller than those for the structure in which thelight-receiving element 270PD and the light-emitting element 270Rinclude separately formed layers. As a result, the number ofmanufacturing steps and the manufacturing cost of the display device canbe reduced.

When the light-receiving element 270PD and the light-emitting element270R have a common structure, a margin for misalignment can be narrowerthan that for the structure in which the light-receiving element 270PDand the light-emitting element 270R include separately formed layers.Accordingly, the aperture ratio of a pixel can be increased, so that thelight extraction efficiency of the display device can be increased. Thiscan extend the life of the light-emitting element. Furthermore, thedisplay device can exhibit a high luminance. Moreover, the resolution ofthe display device can also be increased.

The light-emitting layer 283R contains a light-emitting material thatemits red light. The active layer 273 contains an organic compound thatabsorbs light with a wavelength shorter than that of red light (e.g.,one or both of green light and blue light). The active layer 273preferably contains an organic compound that does not easily absorb redlight and that absorbs light with a wavelength shorter than that of redlight. In this way, red light can be efficiently extracted from thelight-emitting element 270R, and the light-receiving element 270PD candetect light with a wavelength shorter than that of red light at highaccuracy.

Although the light-emitting element 270R and the light-receiving element270PD have the same structure in an example of the display device 280B,the light-emitting element 270R and the light-receiving element 270PDmay include optical adjustment layers with different thicknesses.

A display device 280C illustrated in FIG. 13A and FIG. 13B includes alight-emitting and light-receiving element 270RPD that emits red (R)light and has a light-receiving function, the light-emitting element270G that emits green (G) light, and the light-emitting element 270Bthat emits blue (B) light.

Each of the light-emitting elements includes the pixel electrode 271,the hole-injection layer 281, the hole-transport layer 282, alight-emitting layer, the electron-transport layer 284, theelectron-injection layer 285, and the common electrode 275 which arestacked in this order. The light-emitting element 270G includes thelight-emitting layer 283G, and the light-emitting element 270B includesthe light-emitting layer 283B. The light-emitting layer 283G contains alight-emitting substance that emits green light, and the light-emittinglayer 283B contains a light-emitting substance that emits blue light.

The light-emitting and light-receiving element 270RPD includes the pixelelectrode 271, the hole-injection layer 281, the hole-transport layer282, the active layer 273, the light-emitting layer 283R, theelectron-transport layer 284, the electron-injection layer 285, and thecommon electrode 275 which are stacked in this order.

Note that the light-emitting and light-receiving element 270RPD includedin the display device 280C has the same structure as the light-emittingelement 270R and the light-receiving element 270PD included in thedisplay device 280B. Furthermore, the light-emitting elements 270G and270B included in the display device 280C also have the same structuresas the light-emitting elements 270G and 270B, which are included in thedisplay device 280B.

FIG. 13A illustrates a case where the light-emitting and light-receivingelement 270RPD functions as a light-emitting element. In the example ofFIG. 13A, the light-emitting element 270B emits blue light, thelight-emitting element 270G emits green light, and the light-emittingand light-receiving element 270RPD emits red light.

FIG. 13B illustrates a case where the light-emitting and light-receivingelement 270RPD functions as a light-receiving element. In the example ofFIG. 13B, the light-emitting and light-receiving element 270RPD detectsblue light emitted from the light-emitting element 270B and green lightemitted from the light-emitting element 270G.

The light-emitting element 270B, the light-emitting element 270G, andthe light-emitting and light-receiving element 270RPD each include thepixel electrode 271 and the common electrode 275. In this embodiment,the case where the pixel electrode 271 functions as an anode and thecommon electrode 275 functions as a cathode is described as an example.

In the description made in this embodiment, also in the light-emittingand light-receiving element 270RPD, the pixel electrode 271 functions asan anode and the common electrode 275 functions as a cathode as in thelight-emitting element. In other words, when the light-emitting andlight-receiving element 270RPD is driven by application of reverse biasbetween the pixel electrode 271 and the common electrode 275, lightentering the light-emitting and light-receiving element 270RPD can bedetected and charge can be generated and extracted as current.

Note that it can be said that the light-emitting and light-receivingelement 270RPD illustrated in FIG. 13A and FIG. 13B has a structure inwhich the active layer 273 is added to the light-emitting element. Thatis, the light-emitting and light-receiving element 270RPD can be formedconcurrently with the formation of the light-emitting element only byadding a step of depositing the active layer 273 in the manufacturingprocess of the light-emitting element. The light-emitting element andthe light-emitting and light-receiving element can be formed over onesubstrate. Thus, one or both of an image capturing function and asensing function can be provided to the display portion without asignificant increase in the number of manufacturing steps.

The stacking order of the light-emitting layer 283R and the active layer273 is not limited. FIG. 13A and FIG. 13B each illustrate an example inwhich the active layer 273 is provided over the hole-transport layer282, and the light-emitting layer 283R is provided over the active layer273. The light-emitting layer 283R may be provided over thehole-transport layer 282, and the active layer 273 may be provided overthe light-emitting layer 283R.

As illustrated in FIG. 13A and FIG. 13B, the active layer 273 and thelight-emitting layer 283R may be in contact with each other.Furthermore, a buffer layer may be interposed between the active layer273 and the light-emitting layer 283R. As the buffer layer, at least onelayer of a hole-injection layer, a hole-transport layer, anelectron-transport layer, an electron-injection layer, a hole-blockinglayer, an electron-blocking layer, and the like can be used.

The buffer layer provided between the active layer 273 and thelight-emitting layer 283R can inhibit transfer of excitation energy fromthe light-emitting layer 283R to the active layer 273. Furthermore, thebuffer layer can also be used to adjust the optical path length (cavitylength) of the microcavity structure. Thus, high emission efficiency canbe obtained from a light-emitting and light-receiving element includingthe buffer layer between the active layer 273 and the light-emittinglayer 283R.

The light-emitting and light-receiving element may exclude at least onelayer of the hole-injection layer 281, the hole-transport layer 282, theelectron-transport layer 284, and the electron-injection layer 285.Furthermore, the light-emitting and light-receiving element may includeanother functional layer such as a hole-blocking layer or anelectron-blocking layer.

The light-emitting and light-receiving element may include a layer thatserves as both a light-emitting layer and an active layer withoutincluding the active layer 273 and the light-emitting layer 283R. As thelayer serving as both a light-emitting layer and an active layer, alayer containing three materials which are an n-type semiconductor thatcan be used for the active layer 273, a p-type semiconductor that can beused for the active layer 273, and a light-emitting substance that canbe used for the light-emitting layer 283R can be used, for example.

Note that an absorption band on the lowest energy side of an absorptionspectrum of a mixed material of the n-type semiconductor and the p-typesemiconductor and a maximum peak of an emission spectrum (PL spectrum)of the light-emitting substance preferably do not overlap with eachother and are further preferably positioned fully apart from each other.

In the light-emitting and light-receiving element, a conductive filmthat transmits visible light is used as the electrode through whichlight is extracted. A conductive film that reflects visible light ispreferably used as the electrode through which light is not extracted.

The functions and materials of the layers constituting thelight-emitting and light-receiving element are similar to those of thelayers constituting the light-emitting elements and the light-receivingelement and are not described in detail.

A detailed structure of the display device of one embodiment of thepresent invention is described below with reference to FIG. 14 and FIG.15 .

[Display Device 100A]

FIG. 14A is a cross-sectional view of a display device 100A.

The display device 100A includes a light-receiving element 110 and alight-emitting element 190.

The light-emitting element 190 includes a pixel electrode 191, a bufferlayer 192, a light-emitting layer 193, a buffer layer 194, and a commonelectrode 115 which are stacked in this order. The buffer layer 192 caninclude one or both of a hole-injection layer and a hole-transportlayer. The light-emitting layer 193 contains an organic compound. Thebuffer layer 194 can include one or both of an electron-injection layerand an electron-transport layer. The light-emitting element 190 has afunction of emitting visible light 121. Note that the display device100A may also include a light-emitting element having a function ofemitting infrared light.

The light-receiving element 110 includes the pixel electrode 191, abuffer layer 182, an active layer 183, a buffer layer 184, and thecommon electrode 115 which are stacked in this order. The buffer layer182 can include a hole-transport layer. The active layer 183 contains anorganic compound. The buffer layer 184 can include an electron-transportlayer. The light-receiving element 110 has a function of detectingvisible light. Note that the light-receiving element 110 may also have afunction of detecting infrared light.

This embodiment is described assuming that the pixel electrode 191functions as an anode and the common electrode 115 functions as acathode in both of the light-emitting element 190 and thelight-receiving element 110. In other words, the light-receiving element110 is driven by application of reverse bias between the pixel electrode191 and the common electrode 115, so that light entering thelight-receiving element 110 can be detected and charge can be generatedand extracted as current in the display device 100A.

The pixel electrode 191, the buffer layer 182, the buffer layer 192, theactive layer 183, the light-emitting layer 193, the buffer layer 184,the buffer layer 194, and the common electrode 115 may each have asingle-layer structure or a stacked-layer structure.

The pixel electrodes 191 are positioned over an insulating layer 214.The pixel electrodes 191 can be formed using the same material in thesame step. End portions of the pixel electrodes 191 are covered with apartition 216. The two pixel electrodes 191 adjacent to each other areelectrically insulated (electrically isolated) from each other by thepartition 216.

An organic insulating film is suitable for the partition 216. Examplesof materials that can be used for the organic insulating film include anacrylic resin, a polyimide resin, an epoxy resin, a polyamide resin, apolyimide-amide resin, a siloxane resin, a benzocyclobutene-based resin,a phenol resin, and precursors of these resins. The partition 216 is alayer that transmits visible light. A partition that blocks visiblelight may be provided instead of the partition 216.

The common electrode 115 is a layer shared by the light-receivingelement 110 and the light-emitting element 190.

The material, thickness, and the like of the pair of electrodes can bethe same between the light-receiving element 110 and the light-emittingelement 190. Accordingly, the manufacturing cost of the display devicecan be reduced and the manufacturing process of the display device canbe simplified.

The display device 100A includes the light-receiving element 110, thelight-emitting element 190, a transistor 131, a transistor 132, and thelike between a pair of substrates (a substrate 151 and a substrate 152).

In the light-receiving element 110, the buffer layer 182, the activelayer 183, and the buffer layer 184, which are positioned between thepixel electrode 191 and the common electrode 115, can each be referredto as an organic layer (a layer containing an organic compound). Thepixel electrode 191 preferably has a function of reflecting visiblelight. The common electrode 115 has a function of transmitting visiblelight. Note that in the case where the light-receiving element 110 isconfigured to detect infrared light, the common electrode 115 has afunction of transmitting infrared light. Furthermore, the pixelelectrode 191 preferably has a function of reflecting infrared light.

The light-receiving element 110 has a function of detecting light.Specifically, the light-receiving element 110 is a photoelectricconversion element that receives light 122 entering from the outside ofthe display device 100A and converts it into an electric signal. Thelight 122 can also be expressed as light that is emitted from thelight-emitting element 190 and then reflected by an object. The light122 may enter the light-receiving element 110 through a lens or the likeprovided in the display device 100A.

In the light-emitting element 190, the buffer layer 192, thelight-emitting layer 193, and the buffer layer 194, which are positionedbetween the pixel electrode 191 and the common electrode 115, can becollectively referred to as an EL layer. The EL layer includes at leastthe light-emitting layer 193. As described above, the pixel electrode191 preferably has a function of reflecting visible light. The commonelectrode 115 has a function of transmitting visible light. Note that inthe case where the display device 100A includes a light-emitting elementthat emits infrared light, the common electrode 115 has a function oftransmitting infrared light. Furthermore, the pixel electrode 191preferably has a function of reflecting infrared light.

The light-emitting element included in the display device of thisembodiment preferably employs a micro optical resonator (microcavity)structure.

The buffer layer 192 or the buffer layer 194 may have a function as anoptical adjustment layer. By changing the thickness of the buffer layer192 or the buffer layer 194, light of a particular color can beintensified and taken out from each light-emitting element.

The light-emitting element 190 has a function of emitting visible light.Specifically, the light-emitting element 190 is an electroluminescentelement that emits light to the substrate 152 side by applying voltagebetween the pixel electrode 191 and the common electrode 115 (see thevisible light 121).

The pixel electrode 191 included in the light-receiving element 110 iselectrically connected to a source or a drain of the transistor 131through an opening provided in the insulating layer 214.

The pixel electrode 191 included in the light-emitting element 190 iselectrically connected to a source or a drain of the transistor 132through an opening provided in the insulating layer 214.

The transistor 131 and the transistor 132 are on and in contact with thesame layer (the substrate 151 in FIG. 14A).

At least part of a circuit electrically connected to the light-receivingelement 110 and a circuit electrically connected to the light-emittingelement 190 are preferably formed using the same material in the samestep. In that case, the thickness of the display device can be reducedcompared with the case where the two circuits are separately formed,resulting in simplification of the manufacturing steps.

The light-receiving element 110 and the light-emitting element 190 arepreferably covered with a protective layer 116. In FIG. 14A, theprotective layer 116 is provided on and in contact with the commonelectrode 115. Providing the protective layer 116 can inhibit entry ofimpurities such as water into the light-receiving element 110 and thelight-emitting element 190, so that the reliability of thelight-receiving element 110 and the light-emitting element 190 can beincreased. The protective layer 116 and the substrate 152 are bonded toeach other with an adhesive layer 142.

A light shielding layer 158 is provided on a surface of the substrate152 on the substrate 151 side. The light shielding layer 158 hasopenings in a position overlapping with the light-emitting element 190and in a position overlapping with the light-receiving element 110.

Here, the light-receiving element 110 detects light that is emitted fromthe light-emitting element 190 and then reflected by an object. However,in some cases, light emitted from the light-emitting element 190 isreflected inside the display device 100A and enters the light-receivingelement 110 without through an object. The light shielding layer 158 canreduce the influence of such stray light. For example, in the case wherethe light shielding layer 158 is not provided, light 123 emitted fromthe light-emitting element 190 is reflected by the substrate 152 andreflected light 124 enters the light-receiving element 110 in somecases. Providing the light shielding layer 158 can inhibit entry of thereflected light 124 into the light-receiving element 110. Consequently,noise can be reduced, and the sensitivity of a sensor using thelight-receiving element 110 can be increased.

For the light shielding layer 158, a material that blocks light emittedfrom the light-emitting element can be used. The light shielding layer158 preferably absorbs visible light. As the light shielding layer 158,a black matrix can be formed using a metal material or a resin materialcontaining pigment (e.g., carbon black) or dye, for example. The lightshielding layer 158 may have a stacked-layer structure of a red colorfilter, a green color filter, and a blue color filter.

[Display Device 100B]

FIG. 14B and FIG. 14C illustrate cross-sectional views of a displaydevice 100B. Note that in the description of the display device below,components similar to those of the above-mentioned display device arenot described in some cases.

The display device 100B includes a light-emitting element 190B, alight-emitting element 190G, and a light-emitting and light-receivingelement 190RPD.

The light-emitting element 190B includes the pixel electrode 191, abuffer layer 192B, a light-emitting layer 193B, a buffer layer 194B, andthe common electrode 115 which are stacked in this order. Thelight-emitting element 190B has a function of emitting blue light 121B.

The light-emitting element 190G includes the pixel electrode 191, abuffer layer 192G, a light-emitting layer 193G, a buffer layer 194G, andthe common electrode 115 which are stacked in this order. Thelight-emitting element 190G has a function of emitting green light 121G.

The light-emitting and light-receiving element 190RPD includes the pixelelectrode 191, a buffer layer 192R, the active layer 183, alight-emitting layer 193R, a buffer layer 194R, and the common electrode115 which are stacked in this order. The light-emitting andlight-receiving element 190RPD has a function of emitting red light 121Rand a function of detecting the light 122.

FIG. 14B illustrates a case where the light-emitting and light-receivingelement 190RPD functions as a light-emitting element. FIG. 14Billustrates an example in which the light-emitting element 190B emitsblue light, the light-emitting element 190G emits green light, and thelight-emitting and light-receiving element 190RPD emits red light.

FIG. 14C illustrates a case where the light-emitting and light-receivingelement 190RPD functions as a light-receiving element. FIG. 14Cillustrates an example in which the light-emitting and light-receivingelement 190RPD detects blue light emitted from the light-emittingelement 190B and green light emitted from the light-emitting element190G.

The display device 100B includes the light-emitting and light-receivingelement 190RPD, the light-emitting element 190G, the light-emittingelement 190B, the transistor 132, and the like between the pair ofsubstrates (the substrate 151 and the substrate 152).

The pixel electrode 191 is positioned over the insulating layer 214. Thetwo pixel electrodes 191 adjacent to each other are electricallyinsulated from each other by the partition 216. The pixel electrode 191is electrically connected to the source or the drain of the transistor132 through the opening provided in the insulating layer 214.

The light-emitting and light-receiving element and the light-emittingelements are preferably covered with the protective layer 116. Theprotective layer 116 and the substrate 152 are bonded to each other withthe adhesive layer 142. The light shielding layer 158 is provided on thesurface of the substrate 152 on the substrate 151 side.

[Display Device 100C]

FIG. 15A illustrates a cross-sectional view of a display device 100C.

The display device 100C includes the light-receiving element 110 and thelight-emitting element 190.

The light-emitting element 190 includes the pixel electrode 191, acommon layer 112, the light-emitting layer 193, a common layer 114, andthe common electrode 115 in this order. The common layer 112 can includeone or both of a hole-injection layer and a hole-transport layer. Thelight-emitting layer 193 contains an organic compound. The common layer114 can include one or both of an electron-injection layer and anelectron-transport layer. The light-emitting element 190 has a functionof emitting visible light. Note that the display device 100C may alsoinclude a light-emitting element having a function of emitting infraredlight.

The light-receiving element 110 includes the pixel electrode 191, thecommon layer 112, the active layer 183, the common layer 114, and thecommon electrode 115 which are stacked in this order. The active layer183 contains an organic compound. The light-receiving element 110 has afunction of detecting visible light. Note that the light-receivingelement 110 may also have a function of detecting infrared light.

The pixel electrode 191, the common layer 112, the active layer 183, thelight-emitting layer 193, the common layer 114, and the common electrode115 may each have a single-layer structure or a stacked-layer structure.

The pixel electrode 191 is positioned over the insulating layer 214. Thetwo pixel electrodes 191 adjacent to each other are electricallyinsulated from each other by the partition 216. The pixel electrode 191is electrically connected to the source or the drain of the transistor132 through the opening provided in the insulating layer 214.

The common layer 112, the common layer 114, and the common electrode 115are layers shared by the light-receiving element 110 and thelight-emitting element 190. At least some of the layers constituting thelight-receiving element 110 and the light-emitting element 190 arepreferably shared, so that the number of manufacturing steps of thedisplay device can be reduced.

The display device 100C includes the light-receiving element 110, thelight-emitting element 190, the transistor 131, the transistor 132, andthe like between the pair of substrates (the substrate 151 and thesubstrate 152).

The light-receiving element 110 and the light-emitting element 190 arepreferably covered with the protective layer 116. The protective layer116 and the substrate 152 are bonded to each other with the adhesivelayer 142.

A resin layer 159 is provided on the surface of the substrate 152 on thesubstrate 151 side. The resin layer 159 is provided in a positionoverlapping with the light-emitting element 190 and is not provided in aposition overlapping with the light-receiving element 110.

The resin layer 159 can be provided in the position overlapping with thelight-emitting element 190 and have an opening 159 p in the positionoverlapping with the light-receiving element 110, as illustrated in FIG.15B, for example. Alternatively, as illustrated in FIG. 15C, the resinlayer 159 can be provided to have an island shape in a positionoverlapping with the light-emitting element 190 but not in a positionoverlapping with the light-receiving element 110.

The light shielding layer 158 is provided on the surface of thesubstrate 152 on the substrate 151 side and on a surface of the resinlayer 159 on the substrate 151 side. The light shielding layer 158 hasopenings in a position overlapping with the light-emitting element 190and in a position overlapping with the light-receiving element 110.

Here, the light-receiving element 110 detects light that is emitted fromthe light-emitting element 190 and then reflected by an object. However,in some cases, light emitted from the light-emitting element 190 isreflected inside the display device 100C and enters the light-receivingelement 110 without through an object. The light shielding layer 158 canabsorb such stray light and thereby reduce entry of stray light into thelight-receiving element 110. For example, the light shielding layer 158can absorb stray light 123 a that has passed through the resin layer 159and has been reflected by the surface of the substrate 152 on thesubstrate 151 side. Moreover, the light shielding layer 158 can absorbstray light 123 b before the stray light 123 b reaches the resin layer159. This can inhibit stray light from entering the light-receivingelement 110. Consequently, noise can be reduced, and the sensitivity ofa sensor using the light-receiving element 110 can be increased. It isparticularly preferable that the light shielding layer 158 be positionedclose to the light-emitting element 190, in which case stray light canbe further reduced. This is preferable also in terms of improvingdisplay quality, because the light shielding layer 158 positioned closeto the light-emitting element 190 can inhibit viewing angle dependenceof display.

Providing the light shielding layer 158 can control the range where thelight-receiving element 110 detects light. When the light shieldinglayer 158 is positioned apart from the light-receiving element 110, theimage-capturing range is narrowed, and the image-capturing resolutioncan be increased.

In the case where the resin layer 159 has an opening, the lightshielding layer 158 preferably covers at least part of the opening andat least part of the side surface of the resin layer 159 exposed in theopening.

In the case where the resin layer 159 is provided in an island shape,the light shielding layer 158 preferably covers at least part of theside surface of the resin layer 159.

Since the light shielding layer 158 is provided along the shape of theresin layer 159 in such a manner, the distance from the light shieldinglayer 158 to the light-emitting element 190 (specifically, thelight-emitting region of the light-emitting element 190) is shorter thanthe distance from the light shielding layer 158 to the light-receivingelement 110 (specifically, the light-receiving region of thelight-receiving element 110). Accordingly, noise of the sensor can bereduced, the imaging resolution can be increased, and viewing angledependence of display can be inhibited. Thus, both the display qualityand the imaging quality of the display device can be increased.

The resin layer 159 is a layer that transmits light emitted from thelight-emitting element 190. Examples of materials for the resin layer159 include an acrylic resin, a polyimide resin, an epoxy resin, apolyamide resin, a polyimide-amide resin, a siloxane resin, abenzocyclobutene-based resin, a phenol resin, and precursors of theseresins. Note that a component provided between the substrate 152 and thelight shielding layer 158 is not limited to the resin layer and may bean inorganic insulating film or the like. As the component becomesthicker, a larger difference occurs between the distance from the lightshielding layer to the light-receiving element and the distance from thelight shielding layer to the light-emitting element. An organicinsulating film made of a resin or the like is suitable for thecomponent because it is easily formed to have a large thickness.

In order to compare the distance from the light shielding layer 158 tothe light-receiving element 110 and the distance from the lightshielding layer 158 to the light-emitting element 190, it is possible touse, for example, the shortest distance L1 from an end portion of thelight shielding layer 158 on the light-receiving element 110 side to thecommon electrode 115 and the shortest distance L2 from an end portion ofthe light shielding layer 158 on the light-emitting element 190 side tothe common electrode 115. With the shortest distance L2 smaller than theshortest distance L1, stray light from the light-emitting element 190can be inhibited, and the sensitivity of the sensor using thelight-receiving element 110 can be increased. Furthermore, viewing angledependence of display can be inhibited. With the shortest distance L1larger than the shortest distance L2, the image-capturing range of thelight-receiving element 110 can be narrowed, and the image-capturingresolution can be increased.

In addition, when the adhesive layer 142 is provided such that a portionoverlapping with the light-receiving element 110 is made thicker than aportion overlapping with the light-emitting element 190, a differencealso can be made between the distance from the light shielding layer 158to the light-receiving element 110 and the distance from the lightshielding layer 158 to the light-emitting element 190.

A more detailed structure of the display device of one embodiment of thepresent invention is described below with reference to FIG. 16 to FIG.19 .

[Display Device 100D]

FIG. 16 illustrates a perspective view of a display device 100D, andFIG. 17 illustrates a cross-sectional view of the display device 100D.

The display device 100D has a structure in which the substrate 152 andthe substrate 151 are bonded to each other. In FIG. 16 , the substrate152 is denoted by a dashed line.

The display device 100D includes a display portion 162, a circuit 164, awiring 165, and the like. FIG. 16 illustrates an example in which an IC173 and an FPC 172 are integrated on the display device 100D. Thus, thestructure illustrated in FIG. 16 can be regarded as a display moduleincluding the display device 100D, the IC (integrated circuit), and theFPC (Flexible Printed Circuit).

As the circuit 164, for example, a scan line driver circuit can be used.

The wiring 165 has a function of supplying a signal and power to thedisplay portion 162 and the circuit 164. The signal and power are inputto the wiring 165 from the outside through the FPC 172 or from the IC173.

FIG. 16 illustrates an example in which the IC 173 is provided over thesubstrate 151 by a COG (Chip On Glass) method, a COF (Chip On Film)method, or the like. An IC including a scan line driver circuit, asignal line driver circuit, or the like can be used as the IC 173, forexample. Note that the display device 100D and the display module mayhave a structure that is not provided with an IC. The IC may be providedover the FPC by a COF method or the like.

FIG. 17 illustrates an example of cross sections of part of a regionincluding the FPC 172, part of a region including the circuit 164, partof a region including the display portion 162, and part of a regionincluding an end portion of the display device 100D illustrated in FIG.16 .

The display device 100D illustrated in FIG. 17 includes a transistor241, a transistor 245, a transistor 246, a transistor 247, thelight-emitting element 190B, the light-emitting element 190G, thelight-emitting and light-receiving element 190RPD, and the like betweenthe substrate 151 and the substrate 152.

The substrate 152 and the protective layer 116 are bonded to each otherwith the adhesive layer 142. A solid sealing structure, a hollow sealingstructure, or the like can be employed to seal the light-emittingelement 190B, the light-emitting element 190G, and the light-emittingand light-receiving element 190RPD. In FIG. 17 , a space surrounded bythe substrate 152, the adhesive layer 142, and the insulating layer 214is sealed with the adhesive layer 142, and the solid sealing structureis employed.

The light-emitting element 190B has a stacked-layer structure in whichthe pixel electrode 191, the common layer 112, the light-emitting layer193B, the common layer 114, and the common electrode 115 are stacked inthis order from the insulating layer 214 side. The pixel electrode 191is connected to a conductive layer 222 b included in the transistor 247through an opening provided in the insulating layer 214. The transistor247 has a function of controlling the driving of the light-emittingelement 190B. The end portion of the pixel electrode 191 is covered withthe partition 216. The pixel electrode 191 contains a material thatreflects visible light, and the common electrode 115 contains a materialthat transmits visible light.

The light-emitting element 190G has a stacked-layer structure in whichthe pixel electrode 191, the common layer 112, the light-emitting layer193G, the common layer 114, and the common electrode 115 are stacked inthis order from the insulating layer 214 side. The pixel electrode 191is connected to the conductive layer 222 b included in the transistor246 through an opening provided in the insulating layer 214. Thetransistor 246 has a function of controlling the driving of thelight-emitting element 190G.

The light-emitting and light-receiving element 190RPD has astacked-layer structure in which the pixel electrode 191, the commonlayer 112, the active layer 183, the light-emitting layer 193R, thecommon layer 114, and the common electrode 115 are stacked in this orderfrom the insulating layer 214 side. The pixel electrode 191 iselectrically connected to the conductive layer 222 b included in thetransistor 245 through an opening provided in the insulating layer 214.The transistor 245 has a function of controlling the driving of thelight-emitting and light-receiving element 190RPD.

Light emitted from the light-emitting element 190B, the light-emittingelement 190G, and the light-emitting and light-receiving element 190RPDis emitted toward the substrate 152 side. Light enters thelight-emitting and light-receiving element 190RPD through the substrate152 and the adhesive layer 142. For the substrate 152 and the adhesivelayer 142, a material having a high visible-light-transmitting propertyis preferably used.

The pixel electrodes 191 included in the light-emitting element 190B,the light-emitting element 190G, and the light-emitting andlight-receiving element 190RPD can be formed using the same material inthe same step. The common layer 112, the common layer 114, and thecommon electrode 115 are used in common in the light-emitting element190B, the light-emitting element 190G, and the light-emitting andlight-receiving element 190RPD. The light-emitting and light-receivingelement 190RPD has the structure of the red-light-emitting element towhich the active layer 183 is added. The light-emitting element 190B,the light-emitting element 190G, and the light-emitting andlight-receiving element 190RPD can have a common structure except forthe active layer 183 and the light-emitting layer 193 of each color.Thus, the display portion 162 of the display device 100D can have alight-receiving function without a significant increase in the number ofmanufacturing steps.

The light shielding layer 158 is provided on the surface of thesubstrate 152 on the substrate 151 side. The light shielding layer 158includes openings in positions overlapping with the light-emittingelement 190B, the light-emitting element 190G, and the light-emittingand light-receiving element 190RPD. Providing the light shielding layer158 can control the range where the light-emitting and light-receivingelement 190RPD detects light. As described above, it is preferable tocontrol light entering the light-emitting and light-receiving element byadjusting the position of the opening of the light shielding layerprovided in a position overlapping with the light-emitting andlight-receiving element 190RPD. Furthermore, with the light shieldinglayer 158, light can be inhibited from directly entering thelight-emitting and light-receiving element 190RPD from thelight-emitting element 190 without through an object. Hence, a sensorwith less noise and high sensitivity can be obtained.

The transistor 241, the transistor 245, the transistor 246, and thetransistor 247 are formed over the substrate 151. These transistors canbe formed using the same materials in the same steps.

An insulating layer 211, an insulating layer 213, an insulating layer215, and the insulating layer 214 are provided in this order over thesubstrate 151. Parts of the insulating layer 211 function as gateinsulating layers of the transistors. Parts of the insulating layer 213function as gate insulating layers of the transistors. The insulatinglayer 215 is provided to cover the transistors. The insulating layer 214is provided to cover the transistors and has a function of aplanarization layer. Note that there is no limitation on the number ofgate insulating layers and the number of insulating layers covering thetransistors, and each insulating layer may have either a single layer ortwo or more layers.

A material into which impurities such as water and hydrogen do noteasily diffuse is preferably used for at least one of the insulatinglayers that cover the transistors. This allows the insulating layer toserve as a barrier layer. Such a structure can effectively inhibitdiffusion of impurities into the transistors from the outside andincrease the reliability of the display device.

An inorganic insulating film is preferably used as each of theinsulating layer 211, the insulating layer 213, and the insulating layer215. As the inorganic insulating film, a silicon nitride film, a siliconoxynitride film, a silicon oxide film, a silicon nitride oxide film, analuminum oxide film, or an aluminum nitride film can be used, forexample. A hafnium oxide film, a hafnium oxynitride film, a hafniumnitride oxide film, an yttrium oxide film, a zirconium oxide film, agallium oxide film, a tantalum oxide film, a magnesium oxide film, alanthanum oxide film, a cerium oxide film, a neodymium oxide film, orthe like may be used. A stack including two or more of the aboveinsulating films may also be used. Note that a base film may be providedbetween the substrate 151 and the transistors. Any of theabove-described inorganic insulating films can be used as the base film.

Here, an organic insulating film often has a lower barrier property thanan inorganic insulating film. Therefore, the organic insulating filmpreferably has an opening in the vicinity of the end portion of thedisplay device 100D. This can inhibit entry of impurities from the endportion of the display device 100D through the organic insulating film.Alternatively, the organic insulating film may be formed such that anend portion of the organic insulating film is positioned on the innerside compared to the end portion of the display device 100D, to preventthe organic insulating film from being exposed at the end portion of thedisplay device 100D.

An organic insulating film is suitable for the insulating layer 214functioning as a planarization layer. Examples of materials that can beused for the organic insulating film include an acrylic resin, apolyimide resin, an epoxy resin, a polyamide resin, a polyimide-amideresin, a siloxane resin, a benzocyclobutene-based resin, a phenol resin,and precursors of these resins.

By provision of the protective layer 116 that covers the light-emittingelement 190B, the light-emitting element 190G, and the light-emittingand light-receiving element 190RPD, impurities such as water can beinhibited from entering the light-emitting element 190B, thelight-emitting element 190G, and the light-emitting and light-receivingelement 190RPD, leading to an increase in the reliability of thelight-emitting element 190B, the light-emitting element 190G, and thelight-emitting and light-receiving element 190RPD.

In a region 228 illustrated in FIG. 17 , an opening is formed in theinsulating layer 214. This can inhibit entry of impurities into thedisplay portion 162 from the outside through the insulating layer 214even when an organic insulating film is used as the insulating layer214. Thus, the reliability of the display device 100D can be increased.

In the region 228 in the vicinity of the end portion of the displaydevice 100D, the insulating layer 215 and the protective layer 116 arepreferably in contact with each other through the opening in theinsulating layer 214. In particular, the inorganic insulating filmincluded in the insulating layer 215 and the inorganic insulating filmincluded in the protective layer 116 are preferably in contact with eachother. Thus, entry of impurities from the outside into the displayportion 162 through the organic insulating film can be inhibited. Thus,the reliability of the display device 100D can be increased.

The protective layer 116 may have a single-layer structure or astacked-layer structure. For example, the protective layer 116 may havea stacked-layer structure of an organic insulating film and an inorganicinsulating film. In that case, an end portion of the inorganicinsulating film preferably extends beyond an end portion of the organicinsulating film.

Each of the transistor 241, the transistor 245, the transistor 246, andthe transistor 247 includes a conductive layer 221 functioning as agate, the insulating layer 211 functioning as the gate insulating layer,a conductive layer 222 a and the conductive layer 222 b functioning as asource and a drain, a semiconductor layer 231, the insulating layer 213functioning as the gate insulating layer, and a conductive layer 223functioning as a gate. Here, a plurality of layers obtained byprocessing the same conductive film are illustrated with the samehatching pattern. The insulating layer 211 is positioned between theconductive layer 221 and the semiconductor layer 231. The insulatinglayer 213 is positioned between the conductive layer 223 and thesemiconductor layer 231.

There is no particular limitation on the structure of the transistorsincluded in the display device of this embodiment. For example, a planartransistor, a staggered transistor, or an inverted staggered transistorcan be used. A top-gate or a bottom-gate transistor structure may beemployed. Alternatively, gates may be provided above and below asemiconductor layer in which a channel is formed.

The structure in which the semiconductor layer where a channel is formedis provided between two gates is used for the transistor 241, thetransistor 245, the transistor 246, and the transistor 247. The twogates may be connected to each other and supplied with the same signalto drive the transistor. Alternatively, a potential for controlling thethreshold voltage may be supplied to one of the two gates and apotential for driving may be supplied to the other to control thethreshold voltage of the transistor.

There is no particular limitation on the crystallinity of asemiconductor material used in the transistor, and any of an amorphoussemiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. A semiconductor having crystallinity ispreferably used, in which case deterioration of the transistorcharacteristics can be inhibited.

A semiconductor layer of a transistor preferably includes a metal oxide(also referred to as an oxide semiconductor). Alternatively, thesemiconductor layer of the transistor may include silicon. Examples ofsilicon include amorphous silicon and crystalline silicon (e.g.,low-temperature polysilicon or single crystal silicon).

The semiconductor layer preferably contains indium, M (M is one or morekinds selected from gallium, aluminum, silicon, boron, yttrium, tin,copper, vanadium, beryllium, titanium, iron, nickel, germanium,zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum,tungsten, and magnesium), and zinc, for example. Specifically, M ispreferably one or more kinds selected from aluminum, gallium, yttrium,and tin.

It is particularly preferable to use an oxide containing indium (In),gallium (Ga), and zinc (Zn) (also referred to as IGZO) for thesemiconductor layer.

When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of Inis preferably greater than or equal to the atomic ratio of M in theIn-M-Zn oxide. Examples of the atomic ratio of the metal elements insuch an In-M-Zn oxide include In:M:Zn=1:1:1 or a composition in theneighborhood thereof, In:M:Zn=1:1:1.2 or a composition in theneighborhood thereof, In:M:Zn=2:1:3 or a composition in the neighborhoodthereof, In:M:Zn=3:1:2 or a composition in the neighborhood thereof,In:M:Zn=4:2:3 or a composition in the neighborhood thereof,In:M:Zn=4:2:4.1 or a composition in the neighborhood thereof,In:M:Zn=5:1:3 or a composition in the neighborhood thereof,In:M:Zn=5:1:6 or a composition in the neighborhood thereof,In:M:Zn=5:1:7 or a composition in the neighborhood thereof,In:M:Zn=5:1:8 or a composition in the neighborhood thereof,In:M:Zn=6:1:6 or a composition in the neighborhood thereof, andIn:M:Zn=5:2:5 or a composition in the neighborhood thereof. Note that acomposition in the neighborhood includes the range of ±30% of anintended atomic ratio.

For example, when the atomic ratio is described as In:Ga:Zn=4:2:3 or acomposition in the neighborhood thereof, the case is included where theatomic ratio of Ga is greater than or equal to 1 and less than or equalto 3 and the atomic ratio of Zn is greater than or equal to 2 and lessthan or equal to 4 with the atomic ratio of In being 4. When the atomicratio is described as In:Ga:Zn=5:1:6 or a composition in theneighborhood thereof, the case is included where the atomic ratio of Gais greater than 0.1 and less than or equal to 2 and the atomic ratio ofZn is greater than or equal to 5 and less than or equal to 7 with theatomic ratio of In being 5. When the atomic ratio is described asIn:Ga:Zn=1:1:1 or a composition in the neighborhood thereof, the case isincluded where the atomic ratio of Ga is greater than 0.1 and less thanor equal to 2 and the atomic ratio of Zn is greater than 0.1 and lessthan or equal to 2 with the atomic ratio of In being 1.

The transistor included in the circuit 164 and the transistor includedin the display portion 162 may have the same structure or differentstructures. A plurality of transistors included in the circuit 164 mayhave the same structure or two or more kinds of structures. Similarly, aplurality of transistors included in the display portion 162 may havethe same structure or two or more kinds of structures.

A connection portion 244 is provided in a region of the substrate 151that does not overlap with the substrate 152. In the connection portion244, the wiring 165 is electrically connected to the FPC 172 via aconductive layer 166 and a connection layer 242. On the top surface ofthe connection portion 244, the conductive layer 166 obtained byprocessing the same conductive film as the pixel electrode 191 isexposed. Thus, the connection portion 244 and the FPC 172 can beelectrically connected to each other through the connection layer 242.

A variety of optical members can be arranged on an outer surface of thesubstrate 152. Examples of the optical members include a polarizingplate, a retardation plate, a light diffusion layer (a diffusion film orthe like), an anti-reflective layer, and a light-condensing film.Furthermore, an antistatic film inhibiting the attachment of dust, awater repellent film suppressing the attachment of stain, a hard coatfilm inhibiting generation of a scratch caused by the use, a shockabsorbing layer, or the like may be provided on the outer surface of thesubstrate 152.

For each of the substrate 151 and the substrate 152, glass, quartz,ceramic, sapphire, resin, or the like can be used. When a flexiblematerial is used for the substrate 151 and the substrate 152, theflexibility of the display device can be increased.

For the adhesive layer, a variety of curable adhesives, e.g., aphotocurable adhesive such as an ultraviolet curable adhesive, areactive curable adhesive, a thermosetting adhesive, and an anaerobicadhesive can be used. Examples of these adhesives include an epoxyresin, an acrylic resin, a silicone resin, a phenol resin, a polyimideresin, an imide resin, a PVC (polyvinyl chloride) resin, a PVB(polyvinyl butyral) resin, and an EVA (ethylene vinyl acetate) resin. Inparticular, a material with low moisture permeability, such as an epoxyresin, is preferred. Alternatively, a two-component resin may be used.An adhesive sheet or the like may be used.

As the connection layer, an anisotropic conductive film (ACF), ananisotropic conductive paste (ACP), or the like can be used.

For the structures, materials, and the like of the light-emittingelements 190G and 190B and the light-emitting and light-receivingelement 190R⋅PD, the above description can be referred to.

As materials that can be used for a gate, a source, and a drain of atransistor and conductive layers such as a variety of wirings andelectrodes included in a display device, metals such as aluminum,titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum,silver, tantalum, and tungsten, an alloy containing any of these metalsas its main component, and the like can be given. A film containing anyof these materials can be used in a single layer or as a stacked-layerstructure.

As a light-transmitting conductive material, a conductive oxide such asindium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zincoxide containing gallium, or graphene can be used. Alternatively, ametal material such as gold, silver, platinum, magnesium, nickel,tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, ortitanium, or an alloy material containing the metal material can beused. Further alternatively, a nitride of the metal material (e.g.,titanium nitride) or the like may be used. Note that in the case ofusing the metal material or the alloy material (or the nitride thereof),the thickness is preferably set small enough to be able to transmitlight. A stacked-layer film of any of the above materials can be used asa conductive layer. For example, a stacked-layer film of indium tinoxide and an alloy of silver and magnesium, or the like is preferablyused for increased conductivity. These materials can also be used forconductive layers such as a variety of wirings and electrodes thatconstitute a display device, and conductive layers (conductive layersfunctioning as a pixel electrode or a common electrode) included in alight-emitting element and a light-receiving element (or alight-emitting and light-receiving element).

As an insulating material that can be used for each insulating layer,for example, a resin such as an acrylic resin or an epoxy resin, and aninorganic insulating material such as silicon oxide, silicon oxynitride,silicon nitride oxide, silicon nitride, or aluminum oxide can be given.

[Display Device 100E]

FIG. 18 and FIG. 19A illustrate cross-sectional views of a displaydevice 100E. A perspective view of the display device 100E is similar tothat of the display device 100D (FIG. 13 ). FIG. 18 illustrates anexample of cross sections of part of a region including the FPC 172,part of the circuit 164, and part of the display portion 162 in thedisplay device 100E. FIG. 19A illustrates an example of a cross sectionof part of the display portion 162 in the display device 100E. FIG. 18specifically illustrates an example of a cross section of a regionincluding the light-receiving element 110 and the light-emitting element190R that emits red light in the display portion 162. FIG. 19Aspecifically illustrates an example of a cross section of a regionincluding the light-emitting element 190G that emits green light and thelight-emitting element 190B that emits blue light in the display portion162.

The display device 100E illustrated in FIG. 18 and FIG. 19A includes atransistor 243, a transistor 248, a transistor 249, a transistor 240,the light-emitting element 190R, the light-emitting element 190G, thelight-emitting element 190B, the light-receiving element 110, and thelike between a substrate 153 and a substrate 154.

The resin layer 159 and the common electrode 115 are bonded to eachother with the adhesive layer 142, and the display device 100E employs asolid sealing structure.

The substrate 153 and the insulating layer 212 are bonded to each otherwith an adhesive layer 155. The substrate 154 and an insulating layer157 are bonded to each other with an adhesive layer 156.

To fabricate the display device 100E, first, a first formation substrateprovided with the insulating layer 212, the transistors, thelight-receiving element 110, the light-emitting elements, and the likeand a second formation substrate provided with the insulating layer 157,the resin layer 159, the light shielding layer 158, and the like arebonded to each other with the adhesive layer 142. Then, the substrate153 is bonded to a surface exposed by separation of the first formationsubstrate, and the substrate 154 is bonded to a surface exposed byseparation of the second formation substrate, whereby the componentsformed over the first formation substrate and the second formationsubstrate are transferred to the substrate 153 and the substrate 154.The substrate 153 and the substrate 154 preferably have flexibility.Accordingly, the flexibility of the display device 100E can beincreased.

The inorganic insulating film that can be used as the insulating layer211, the insulating layer 213, and the insulating layer 215 can be usedas the insulating layer 212 and the insulating layer 157.

The light-emitting element 190R has a stacked-layer structure in whichthe pixel electrode 191, the common layer 112, the light-emitting layer193R, the common layer 114, and the common electrode 115 are stacked inthis order from an insulating layer 214 b side. The pixel electrode 191is connected to a conductive layer 169 through an opening provided inthe insulating layer 214 b. The conductive layer 169 is connected to theconductive layer 222 b included in the transistor 248 through an openingprovided in an insulating layer 214 a. The conductive layer 222 b isconnected to a low-resistance region 231 n through an opening providedin the insulating layer 215. That is, the pixel electrode 191 iselectrically connected to the transistor 248. The transistor 248 has afunction of controlling the driving of the light-emitting element 190R.

Similarly, the light-emitting element 190G has a stacked-layer structurein which the pixel electrode 191, the common layer 112, thelight-emitting layer 193G, the common layer 114, and the commonelectrode 115 are stacked in this order from the insulating layer 214 bside. The pixel electrode 191 is electrically connected to thelow-resistance region 231 n of the transistor 249 through the conductivelayer 169 and the conductive layer 222 b of the transistor 249. That is,the pixel electrode 191 is electrically connected to the transistor 249.The transistor 249 has a function of controlling the driving of thelight-emitting element 190G.

In addition, the light-emitting element 190B has a stacked-layerstructure in which the pixel electrode 191, the common layer 112, thelight-emitting layer 193B, the common layer 114, and the commonelectrode 115 are stacked in this order from the insulating layer 214 bside. The pixel electrode 191 is electrically connected to thelow-resistance region 231 n of the transistor 240 through the conductivelayer 169 and the conductive layer 222 b of the transistor 240. That is,the pixel electrode 191 is electrically connected to the transistor 240.The transistor 240 has a function of controlling the driving of thelight-emitting element 190B.

The light-receiving element 110 has a stacked-layer structure in whichthe pixel electrode 191, the common layer 112, the active layer 183, thecommon layer 114, and the common electrode 115 are stacked in this orderfrom the insulating layer 214 b side.

The end portion of the pixel electrode 191 is covered with the partition216. The pixel electrode 191 contains a material that reflects visiblelight, and the common electrode 115 contains a material that transmitsvisible light.

Light emitted from the light-emitting elements 190R, 190G, and 190B isemitted toward the substrate 154 side. Light enters the light-receivingelement 110 through the substrate 154 and the adhesive layer 142. Forthe substrate 154, a material having a high visible-light-transmittingproperty is preferably used.

The pixel electrodes 191 can be formed using the same material in thesame step. The common layer 112, the common layer 114, and the commonelectrode 115 are used in common in the light-receiving element 110 andthe light-emitting elements 190R, 190G, and 190B. The light-receivingelement 110 and the light-emitting element of each color can have acommon structure except for the active layer 183 and the light-emittinglayer. Thus, the light-receiving element 110 can be incorporated intothe display device 100E without a significant increase in the number ofmanufacturing steps.

The resin layer 159 and the light shielding layer 158 are provided on asurface of the insulating layer 157 on the substrate 153 side. The resinlayer 159 is provided in positions overlapping with the light-emittingelements 190R, 190G, and 190B and is not provided in a positionoverlapping with the light-receiving element 110. The light shieldinglayer 158 is provided to cover the surface of the insulating layer 157on the substrate 153 side, a side surface of the resin layer 159, and asurface of the resin layer 159 on the substrate 153 side. The lightshielding layer 158 has openings in a position overlapping with thelight-receiving element 110 and in positions overlapping with thelight-emitting elements 190R, 190G, and 190B. Providing the lightshielding layer 158 can control the range where the light-receivingelement 110 detects light. Furthermore, with the light shielding layer158, light can be inhibited from directly entering the light-receivingelement 110 from the light-emitting elements 190R, 190G, and 190Bwithout through an object. Hence, a sensor with less noise and highsensitivity can be obtained. Providing the resin layer 159 allows thedistance from the light shielding layer 158 to the light-emittingelement of each color to be shorter than the distance from the lightshielding layer 158 to the light-receiving element 110. Accordingly,viewing angle dependence of display can be inhibited while noise of thesensor is reduced. Thus, both the display quality and the imagingquality can be increased.

As illustrated in FIG. 18 , the partition 216 has an opening between thelight-receiving element 110 and the light-emitting element 190R. A lightshielding layer 219 a is provided to fill the opening. The lightshielding layer 219 a is positioned between the light-receiving element110 and the light-emitting element 190R. The light shielding layer 219 aabsorbs light emitted from the light-emitting element 190R. This caninhibit stray light from entering the light-receiving element 110.

A spacer 219 b is provided over the partition 216 and positioned betweenthe light-emitting element 190G and the light-emitting element 190B. Atop surface of the spacer 219 b is preferably closer to the lightshielding layer 158 than a top surface of the light shielding layer 219a is. For example, the sum of the height (thickness) of the partition216 and the height (thickness) of the spacer 219 b is preferably largerthan the height (thickness) of the light shielding layer 219 a. Thus,filling with the adhesive layer 142 can be facilitated. As illustratedin FIG. 19A, the light shielding layer 158 may be in contact with thecommon electrode 115 (or the protective layer) in a portion where thespacer 219 b and the light shielding layer 158 overlap with each other.

The connection portion 244 is provided in a region of the substrate 153that does not overlap with the substrate 154. In the connection portion244, the wiring 165 is electrically connected to the FPC 172 through aconductive layer 167, the conductive layer 166, and the connection layer242. The conductive layer 167 can be obtained by processing the sameconductive film as the conductive layer 169. On the top surface of theconnection portion 244, the conductive layer 166 obtained by processingthe same conductive film as the pixel electrode 191 is exposed. Thus,the connection portion 244 and the FPC 172 can be electrically connectedto each other through the connection layer 242.

Each of the transistor 243, the transistor 248, the transistor 249, andthe transistor 240 includes the conductive layer 221 functioning as agate, the insulating layer 211 functioning as a gate insulating layer, asemiconductor layer including a channel formation region 231 i and apair of low-resistance regions 231 n, the conductive layer 222 aconnected to one of the pair of low-resistance regions 231 n, theconductive layer 222 b connected to the other of the pair oflow-resistance regions 231 n, an insulating layer 225 functioning as agate insulating layer, the conductive layer 223 functioning as a gate,and the insulating layer 215 covering the conductive layer 223. Theinsulating layer 211 is positioned between the conductive layer 221 andthe channel formation region 231 i. The insulating layer 225 ispositioned between the conductive layer 223 and the channel formationregion 231 i.

The conductive layer 222 a and the conductive layer 222 b are connectedto the corresponding low-resistance regions 231 n through openingsprovided in the insulating layer 215. One of the conductive layer 222 aand the conductive layer 222 b functions as a source, and the otherfunctions as a drain.

In FIG. 18 and FIG. 19A, the insulating layer 225 overlaps with thechannel formation region 231 i of the semiconductor layer 231 and doesnot overlap with the low-resistance regions 231 n. The structureillustrated in FIG. 18 and FIG. 19A can be formed by processing theinsulating layer 225 using the conductive layer 223 as a mask, forexample. In FIG. 18 and FIG. 19A, the insulating layer 215 is providedto cover the insulating layer 225 and the conductive layer 223, and theconductive layer 222 a and the conductive layer 222 b are connected tothe low-resistance regions 231 n through the openings in the insulatinglayer 215. Furthermore, an insulating layer that covers the transistormay be provided over the conductive layer 222 a and the conductive layer222 b.

Meanwhile, a transistor 252 illustrated in FIG. 19B is an example inwhich the insulating layer 225 covers a top surface and a side surfaceof the semiconductor layer. The conductive layer 222 a and theconductive layer 222 b are connected to the corresponding low-resistanceregions 231 n through openings provided in the insulating layer 225 andthe insulating layer 215.

As described above, in the display device of one embodiment of thepresent invention, the distances between the two light-emitting elementsand the light-receiving element (or the light-emitting andlight-receiving element) differ from each other, and the distances fromthe two light-emitting elements to the opening of the light shieldinglayer overlapping with the light-receiving element (or thelight-emitting and light-receiving element) differ from each other. Withthis structure, the light-receiving element or the light-emitting andlight-receiving element can receive light coming from one of the twolight-emitting elements more than light coming from the other.Accordingly, much light coming from the light-emitting element used as alight source can be made to enter the light-receiving element or thelight-emitting and light-receiving element in the display device of oneembodiment of the present invention, for example.

[Example of Pixel Circuit]

The display device of one embodiment of the present invention includes,in the display portion, first pixel circuits each including alight-receiving element and second pixel circuits each including alight-emitting element. The first pixel circuits and the second pixelcircuits are each arranged in a matrix.

FIG. 20A illustrates an example of the first pixel circuit including alight-receiving element, and FIG. 20B illustrates an example of thesecond pixel circuit including a light-emitting element.

A pixel circuit PIX1 illustrated in FIG. 20A includes a light-receivingelement PD, a transistor M1, a transistor M2, a transistor M3, atransistor M4, and a capacitor C1. Here, an example in which aphotodiode is used as the light-receiving element PD is illustrated.

A cathode of the light-receiving element PD is electrically connected toa wiring V1, and an anode thereof is electrically connected to one of asource and a drain of the transistor M1. A gate of the transistor M1 iselectrically connected to a wiring TX, and the other of the source andthe drain thereof is electrically connected to one electrode of thecapacitor C1, one of a source and a drain of the transistor M2, and agate of the transistor M3. A gate of the transistor M2 is electricallyconnected to a wiring RES, and the other of the source and the drainthereof is electrically connected to a wiring V2. One of a source and adrain of the transistor M3 is electrically connected to a wiring V3, andthe other of the source and the drain thereof is electrically connectedto one of a source and a drain of the transistor M4. A gate of thetransistor M4 is electrically connected to a wiring SE, and the other ofthe source and the drain thereof is electrically connected to a wiringOUT1.

A constant potential is supplied to the wiring V1, the wiring V2, andthe wiring V3. When the light-receiving element PD is driven with areverse bias, a potential lower than the potential of the wiring V1 issupplied to the wiring V2. The transistor M2 is controlled by a signalsupplied to the wiring RES and has a function of resetting the potentialof a node connected to the gate of the transistor M3 to a potentialsupplied to the wiring V2. The transistor M1 is controlled by a signalsupplied to the wiring TX and has a function of controlling the timingat which the potential of the node changes, in accordance with a currentflowing through the light-receiving element PD. The transistor M3functions as an amplifier transistor for performing output in responseto the potential of the node. The transistor M4 is controlled by asignal supplied to the wiring SE and functions as a selection transistorfor reading an output corresponding to the potential of the node by anexternal circuit connected to the wiring OUT1.

A pixel circuit PIX2 illustrated in FIG. 20B includes a light-emittingelement EL, a transistor M5, a transistor M6, a transistor M7, and acapacitor C2. Here, an example in which a light-emitting diode is usedas the light-emitting element EL is illustrated. In particular, anorganic EL element is preferably used as the light-emitting element EL.

A gate of the transistor M5 is electrically connected to a wiring VG,one of a source and a drain thereof is electrically connected to awiring VS, and the other of the source and the drain thereof iselectrically connected to one electrode of the capacitor C2 and a gateof the transistor M6. One of a source and a drain of the transistor M6is electrically connected to a wiring V4, and the other of the sourceand the drain thereof is electrically connected to an anode of thelight-emitting element EL and one of a source and a drain of thetransistor M7. A gate of the transistor M7 is electrically connected toa wiring MS, and the other of the source and the drain thereof iselectrically connected to a wiring OUT2. A cathode of the light-emittingelement EL is electrically connected to a wiring V5.

A constant potential is supplied to the wiring V4 and the wiring V5. Inthe light-emitting element EL, the anode side can have a high potentialand the cathode side can have a lower potential than the anode side. Thetransistor M5 is controlled by a signal supplied to the wiring VG andfunctions as a selection transistor for controlling a selection state ofthe pixel circuit PIX2. The transistor M6 functions as a drivingtransistor that controls a current flowing through the light-emittingelement EL, in accordance with a potential supplied to the gate. Whenthe transistor M5 is in an on state, a potential supplied to the wiringVS is supplied to the gate of the transistor M6, and the emissionluminance of the light-emitting element EL can be controlled inaccordance with the potential. The transistor M7 is controlled by asignal supplied to the wiring MS and has a function of outputting apotential between the transistor M6 and the light-emitting element EL tothe outside through the wiring OUT2.

The wiring V1, to which the cathode of the light-receiving element PD iselectrically connected, and the wiring V5, to which the cathode of thelight-emitting element EL is electrically connected, can be provided inthe same layer and have the same level of potential.

In the display device of one embodiment of the present invention, it ispreferable to use transistors including a metal oxide (also referred toas an oxide semiconductor) in their semiconductor layers where channelsare formed (such transistors are also referred to as OS transistorsbelow) as all the transistors included in the pixel circuit PIX1 and thepixel circuit PIX2. An OS transistor has an extremely low off-statecurrent and enables charge stored in a capacitor that isseries-connected to the transistor to be retained for a long time.Furthermore, power consumption of the display device can be reduced withan OS transistor.

Alternatively, in the display device of one embodiment of the presentinvention, it is preferable to use transistors including silicon intheir semiconductor layers where channels are formed (such transistorsare also referred to as Si transistors below) as all the transistorsincluded in the pixel circuit PIX1 and the pixel circuit PIX2. Assilicon, single crystal silicon, polycrystalline silicon, amorphoussilicon, and the like can be given. It is particularly preferable to usetransistors including low-temperature polysilicon (LTPS) (hereinafteralso referred to as LTPS transistors) in their semiconductor layers. AnLTPS transistor has high field-effect mobility and can operate at highspeed.

With the use of Si transistors such as LTPS transistors, a variety ofcircuits formed using a CMOS circuit and a display portion can be easilyformed on the same substrate. Thus, external circuits mounted on thedisplay device can be simplified, and costs of parts and mounting costscan be reduced.

In the display device of one embodiment of the present invention, twokinds of transistors are preferably used in the pixel circuit PIX1.Specifically, the pixel circuit PIX1 preferably includes an OStransistor and an LTPS transistor. Changing the material of thesemiconductor layer depending on the desired function of the transistorcan increase the quality of the pixel circuit PIX1 and the accuracy ofsensing and image capturing. In that case, in the pixel circuit PIX2,one or both of an OS transistor and an LTPS transistor may be used.

Furthermore, even when two kinds of transistors (e.g., OS transistorsand LTPS transistors) are used in the pixels, using the LTPS transistorsfacilitates formation of a variety of circuits formed using a CMOScircuit and a display portion on the same substrate. Thus, externalcircuits mounted on the display device can be simplified, and costs ofparts and mounting costs can be reduced.

A transistor using a metal oxide having a wider band gap and a lowercarrier density than silicon can achieve an extremely low off-statecurrent. Thus, such a low off-state current enables retention of chargesaccumulated in a capacitor that is series-connected to the transistorfor a long time. Therefore, it is particularly preferable to use OStransistors as the transistor M1, the transistor M2, and the transistorM5 each of which is series-connected to the capacitor C1 or thecapacitor C2.

A Si transistor is preferably used as the transistor M3. This enableshigh-speed reading operation of imaging data.

Note that the display device which includes, in the display portion, thefirst pixel circuits each including a light-receiving element and thesecond pixel circuits each including a light-emitting element can bedriven in any of an image display mode, an image capture mode, and amode of simultaneously performing image display and image capturing. Inthe image display mode, a full-color image can be displayed using thelight-emitting elements, for example. In the image capture mode, animage for image capturing (e.g., a green monochromatic image or a bluemonochromatic image) can be displayed using the light-emitting elementsand image capturing can be performed using the light-receiving elements,for example. Fingerprint authentication can be performed in the imagecapture mode, for example. In the mode of simultaneously performingimage display and image capturing, an image for image capturing can bedisplayed using the light-emitting elements and image capturing can beperformed using the light-receiving elements in some pixels, and afull-color image can be displayed using the light-emitting elements inthe other pixels, for example.

Although the transistors are illustrated as n-channel transistors inFIG. 20A and FIG. 20B, p-channel transistors can alternatively be used.The transistors are not limited to single-gate transistors and mayfurther include a back gate.

One or more layers including one or both of the transistor and thecapacitor are preferably provided to overlap with the light-receivingelement PD or the light-emitting element EL. Thus, the effective area ofeach pixel circuit can be reduced, and a high-resolution display portioncan be achieved.

This embodiment can be combined with the other embodiments asappropriate.

Embodiment 3

In this embodiment, a metal oxide (also referred to as an oxidesemiconductor) that can be used in the OS transistor described in theabove embodiment is described.

The metal oxide preferably contains at least indium or zinc. Inparticular, indium and zinc are preferably contained. In addition,aluminum, gallium, yttrium, tin, or the like is preferably contained.Furthermore, one or more kinds selected from boron, silicon, titanium,iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium,neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the likemay be contained.

The metal oxide can be formed by a sputtering method, a chemical vapordeposition (CVD) method such as a metal organic chemical vapordeposition (MOCVD) method, an atomic layer deposition (ALD) method, orthe like.

<Classification of Crystal Structure>

Amorphous (including a completely amorphous structure), CAAC(c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-alignedcomposite), single-crystal, and polycrystalline (poly crystal)structures can be given as examples of a crystal structure of an oxidesemiconductor.

Note that a crystal structure of a film or a substrate can be evaluatedwith an X-ray diffraction (XRD) spectrum. For example, evaluation ispossible using an XRD spectrum which is obtained by GIXD(Grazing-Incidence XRD) measurement. Note that a GIXD method is alsoreferred to as a thin film method or a Seemann-Bohlin method.

For example, the XRD spectrum of the quartz glass substrate shows a peakwith a substantially bilaterally symmetrical shape. On the other hand,the peak of the XRD spectrum of the IGZO film having a crystal structurehas a bilaterally asymmetrical shape. The asymmetrical peak of the XRDspectrum clearly shows the existence of crystal in the film or thesubstrate. In other words, the crystal structure of the film or thesubstrate cannot be regarded as “amorphous” unless it has a bilaterallysymmetrical peak in the XRD spectrum.

A crystal structure of a film or a substrate can also be evaluated witha diffraction pattern obtained by a nanobeam electron diffraction (NBED)method (such a pattern is also referred to as a nanobeam electrondiffraction pattern). For example, a halo pattern is observed in thediffraction pattern of the quartz glass substrate, which indicates thatthe quartz glass substrate is in an amorphous state. Furthermore, not ahalo pattern but a spot-like pattern is observed in the diffractionpattern of the IGZO film deposited at room temperature. Thus, it issuggested that the IGZO film deposited at room temperature is in anintermediate state, which is neither a crystal state nor an amorphousstate, and it cannot be concluded that the IGZO film is in an amorphousstate.

<<Structure of Oxide Semiconductor>>

Oxide semiconductors might be classified in a manner different from theabove-described one when classified in terms of the structure. Oxidesemiconductors are classified into a single crystal oxide semiconductorand a non-single-crystal oxide semiconductor, for example. Examples ofthe non-single-crystal oxide semiconductor include the above-describedCAAC-OS and nc-OS. Other examples of the non-single-crystal oxidesemiconductor include a polycrystalline oxide semiconductor, anamorphous-like oxide semiconductor (a-like OS), and an amorphous oxidesemiconductor.

Here, the above-described CAAC-OS, nc-OS, and a-like OS are described indetail.

[CAAC-OS]

The CAAC-OS is an oxide semiconductor that has a plurality of crystalregions each of which has c-axis alignment in a particular direction.Note that the particular direction refers to the film thicknessdirection of a CAAC-OS film, the normal direction of the surface wherethe CAAC-OS film is formed, or the normal direction of the surface ofthe CAAC-OS film. The crystal region refers to a region having aperiodic atomic arrangement. When an atomic arrangement is regarded as alattice arrangement, the crystal region also refers to a region with auniform lattice arrangement. The CAAC-OS has a region where a pluralityof crystal regions are connected in the a-b plane direction, and theregion has distortion in some cases. Note that distortion refers to aportion where the direction of a lattice arrangement changes between aregion with a uniform lattice arrangement and another region with auniform lattice arrangement in a region where a plurality of crystalregions are connected. That is, the CAAC-OS is an oxide semiconductorhaving c-axis alignment and having no clear alignment in the a—b planedirection.

Note that each of the plurality of crystal regions is formed of one ormore fine crystals (crystals each of which has a maximum diameter ofless than 10 nm). In the case where the crystal region is formed of onefine crystal, the maximum diameter of the crystal region is less than 10nm. In the case where the crystal region is formed of a large number offine crystals, the size of the crystal region may be approximatelyseveral tens of nanometers.

In the case of an In-M-Zn oxide (the element M is one or more kindsselected from aluminum, gallium, yttrium, tin, titanium, and the like),the CAAC-OS tends to have a layered crystal structure (also referred toas a layered structure) in which a layer containing indium (In) andoxygen (hereinafter, an In layer) and a layer containing the element M,zinc (Zn), and oxygen (hereinafter, an (M,Zn) layer) are stacked. Indiumand the element M can be replaced with each other. Therefore, indium maybe contained in the (M,Zn) layer. In addition, the element M may becontained in the In layer. Note that Zn may be contained in the Inlayer. Such a layered structure is observed as a lattice image in ahigh-resolution TEM (Transmission Electron Microscope) image, forexample.

When the CAAC-OS film is subjected to structural analysis byOut-of-plane XRD measurement with an XRD apparatus using θ/2θ scanning,for example, a peak indicating c-axis alignment is detected at 2θ of 31°or around 31°. Note that the position of the peak indicating c-axisalignment (the value of 2θ) may change depending on the kind,composition, or the like of the metal element contained in the CAAC-OS.

For example, a plurality of bright spots are observed in the electrondiffraction pattern of the CAAC-OS film. Note that one spot and anotherspot are observed point-symmetrically with a spot of the incidentelectron beam passing through a sample (also referred to as a directspot) as the symmetric center.

When the crystal region is observed from the particular direction, alattice arrangement in the crystal region is basically a hexagonallattice arrangement; however, a unit lattice is not always a regularhexagon and is a non-regular hexagon in some cases. A pentagonal latticearrangement, a heptagonal lattice arrangement, and the like are includedin the distortion in some cases. Note that a clear grain boundary cannotbe observed even in the vicinity of the distortion in the CAAC-OS. Thatis, formation of a grain boundary is inhibited by the distortion of alattice arrangement. This is probably because the CAAC-OS can toleratedistortion owing to a low density of arrangement of oxygen atoms in thea-b plane direction, an interatomic bond distance changed bysubstitution of a metal atom, and the like.

Note that a crystal structure in which a clear grain boundary isobserved is what is called polycrystal. It is highly probable that thegrain boundary becomes a recombination center and captures carriers andthus decreases the on-state current and field-effect mobility of atransistor, for example. Thus, the CAAC-OS in which no clear grainboundary is observed is one of crystalline oxides having a crystalstructure suitable for a semiconductor layer of a transistor. Note thatZn is preferably contained to form the CAAC-OS. For example, an In—Znoxide and an In—Ga—Zn oxide are suitable because they can inhibitgeneration of a grain boundary as compared with an In oxide.

The CAAC-OS is an oxide semiconductor with high crystallinity in whichno clear grain boundary is observed. Thus, in the CAAC-OS, a reductionin electron mobility due to the grain boundary is unlikely to occur.Moreover, since the crystallinity of an oxide semiconductor might bedecreased by entry of impurities, formation of defects, or the like, theCAAC-OS can be regarded as an oxide semiconductor that has small amountsof impurities and defects (e.g., oxygen vacancies). Thus, an oxidesemiconductor including the CAAC-OS is physically stable. Therefore, theoxide semiconductor including the CAAC-OS is resistant to heat and hashigh reliability. In addition, the CAAC-OS is stable with respect tohigh temperature in the manufacturing process (what is called thermalbudget). Accordingly, the use of the CAAC-OS for the OS transistor canextend the degree of freedom of the manufacturing process.

[nc-OS]

In the nc-OS, a microscopic region (e.g., a region with a size greaterthan or equal to 1 nm and less than or equal to 10 nm, in particular, aregion with a size greater than or equal to 1 nm and less than or equalto 3 nm) has a periodic atomic arrangement. In other words, the nc-OSincludes a fine crystal. Note that the size of the fine crystal is, forexample, greater than or equal to 1 nm and less than or equal to 10 nm,particularly greater than or equal to 1 nm and less than or equal to 3nm; thus, the fine crystal is also referred to as a nanocrystal.Furthermore, there is no regularity of crystal orientation betweendifferent nanocrystals in the nc-OS. Thus, the orientation in the wholefilm is not observed. Accordingly, the nc-OS cannot be distinguishedfrom an a-like OS or an amorphous oxide semiconductor by some analysismethods. For example, when an nc-OS film is subjected to structuralanalysis by Out-of-plane XRD measurement with an XRD apparatus usingθ/2θscanning, a peak indicating crystallinity is not detected.Furthermore, a diffraction pattern like a halo pattern is observed whenthe nc-OS film is subjected to electron diffraction (also referred to asselected-area electron diffraction) using an electron beam with a probediameter larger than the diameter of a nanocrystal (e.g., larger than orequal to 50 nm). Meanwhile, in some cases, a plurality of spots in aring-like region with a direct spot as the center are observed in ananobeam electron diffraction pattern of the nc-OS film obtained usingan electron beam with a probe diameter nearly equal to or smaller thanthe diameter of a nanocrystal (e.g., 1 nm or larger and 30 nm orsmaller).

[a-like OS]

The a-like OS is an oxide semiconductor having a structure between thoseof the nc-OS and the amorphous oxide semiconductor. The a-like OScontains a void or a low-density region. That is, the a-like OS haslower crystallinity than the nc-OS and the CAAC-OS. Moreover, the a-likeOS has higher hydrogen concentration in the film than the nc-OS and theCAAC-OS.

<<Structure of Oxide Semiconductor>>

Next, the above-described CAC-OS is described in detail. Note that theCAC-OS relates to the material composition.

[CAC-OS]

The CAC-OS refers to one composition of a material in which elementsconstituting a metal oxide are unevenly distributed with a size greaterthan or equal to 0.5 nm and less than or equal to 10 nm, preferablygreater than or equal to 1 nm and less than or equal to 3 nm, or asimilar size, for example. Note that a state in which one or more metalelements are unevenly distributed and regions including the metalelement(s) are mixed with a size greater than or equal to 0.5 nm andless than or equal to 10 nm, preferably greater than or equal to 1 nmand less than or equal to 3 nm, or a similar size in a metal oxide ishereinafter referred to as a mosaic pattern or a patch-like pattern.

In addition, the CAC-OS has a composition in which materials areseparated into a first region and a second region to form a mosaicpattern, and the first regions are distributed in the film (thiscomposition is hereinafter also referred to as a cloud-likecomposition). That is, the CAC-OS is a composite metal oxide having acomposition in which the first regions and the second regions are mixed.

Note that the atomic ratios of In, Ga, and Zn to the metal elementscontained in the CAC-OS in an In—Ga—Zn oxide are denoted by [In], [Ga],and [Zn], respectively. For example, the first region in the CAC-OS inthe In—Ga—Zn oxide has [In] higher than that in the composition of theCAC-OS film. Moreover, the second region has [Ga] higher than that inthe composition of the CAC-OS film. For example, the first region hashigher [In] and lower [Ga] than the second region. Moreover, the secondregion has higher [Ga] and lower [In] than the first region.

Specifically, the first region contains indium oxide, indium zinc oxide,or the like as its main component. The second region contains galliumoxide, gallium zinc oxide, or the like as its main component. That is,the first region can be referred to as a region containing In as itsmain component. The second region can be referred to as a regioncontaining Ga as its main component.

Note that a clear boundary between the first region and the secondregion cannot be observed in some cases.

In a material composition of a CAC-OS in an In—Ga—Zn oxide that containsIn, Ga, Zn, and O, regions containing Ga as a main component areobserved in part of the CAC-OS and regions containing In as a maincomponent are observed in part thereof. These regions are randomlydispersed to form a mosaic pattern. Thus, it is suggested that theCAC-OS has a structure in which metal elements are unevenly distributed.

The CAC-OS can be formed by a sputtering method under a condition wherea substrate is not heated, for example. Moreover, in the case of formingthe CAC-OS by a sputtering method, any one or more selected from aninert gas (typically, argon), an oxygen gas, and a nitrogen gas are usedas a deposition gas. The ratio of the flow rate of an oxygen gas to thetotal flow rate of the deposition gas at the time of deposition ispreferably as low as possible, and for example, the ratio of the flowrate of an oxygen gas to the total flow rate of the deposition gas atthe time of deposition is preferably higher than or equal to 0% and lessthan 30%, further preferably higher than or equal to 0% and less than orequal to 10%.

For example, energy dispersive X-ray spectroscopy (EDX) is used toobtain EDX mapping, and according to the EDX mapping, the CAC-OS in theIn—Ga—Zn oxide has a structure in which the region containing In as itsmain component (the first region) and the region containing Ga as itsmain component (the second region) are unevenly distributed and mixed.

Here, the first region has a higher conductivity than the second region.In other words, when carriers flow through the first region, theconductivity of a metal oxide is exhibited. Accordingly, when the firstregions are distributed in a metal oxide like a cloud, high field-effectmobility (μ) can be achieved.

The second region has a higher insulating property than the firstregion. In other words, when the second regions are distributed in ametal oxide, leakage current can be inhibited.

Thus, in the case where the CAC-OS is used for a transistor, by thecomplementary function of the conducting function due to the firstregion and the insulating function due to the second region, the CAC-OScan have a switching function (On/Off function). That is, the CAC-OS hasa conducting function in part of the material and has an insulatingfunction in another part of the material; as a whole, the CAC-OS has afunction of a semiconductor. Separation of the conducting function andthe insulating function can maximize each function. Accordingly, whenthe CAC-OS is used for a transistor, high on-state current (I_(on)),high field-effect mobility (μ), and excellent switching operation can beachieved.

A transistor using the CAC-OS has high reliability. Thus, the CAC-OS ismost suitable for a variety of semiconductor devices such as displaydevices.

An oxide semiconductor has various structures with different properties.Two or more kinds among the amorphous oxide semiconductor, thepolycrystalline oxide semiconductor, the a-like OS, the CAC-OS, thenc-OS, and the CAAC-OS may be included in an oxide semiconductor of oneembodiment of the present invention.

<Transistor Including Oxide Semiconductor>

Next, the case where the above oxide semiconductor is used for atransistor is described.

When the above oxide semiconductor is used for a transistor, atransistor with high field-effect mobility can be achieved. In addition,a transistor having high reliability can be achieved.

An oxide semiconductor having a low carrier concentration is preferablyused in a transistor. For example, the carrier concentration of an oxidesemiconductor is lower than or equal to 1×10¹⁷ cm⁻³, preferably lowerthan or equal to 1×10¹⁵ cm⁻³, further preferably lower than or equal to1×10¹³ cm⁻³, still further preferably lower than or equal to 1×10¹¹cm⁻³, yet further preferably lower than 1×10¹⁰ cm⁻³, and higher than orequal to 1×10⁻³ cm⁻³. In order to reduce the carrier concentration in anoxide semiconductor film, the impurity concentration in the oxidesemiconductor film is reduced so that the density of defect states canbe reduced. In this specification and the like, a state with a lowimpurity concentration and a low density of defect states is referred toas a highly purified intrinsic or substantially highly purifiedintrinsic state. Note that an oxide semiconductor having a low carrierconcentration may be referred to as a highly purified intrinsic orsubstantially highly purified intrinsic oxide semiconductor.

A highly purified intrinsic or substantially highly purified intrinsicoxide semiconductor film has a low density of defect states and thus hasa low density of trap states in some cases.

Charge trapped by the trap states in the oxide semiconductor takes along time to disappear and might behave like fixed charge. Thus, atransistor whose channel formation region is formed in an oxidesemiconductor with a high density of trap states has unstable electricalcharacteristics in some cases.

Accordingly, in order to obtain stable electrical characteristics of atransistor, reducing the impurity concentration in an oxidesemiconductor is effective. In order to reduce the impurityconcentration in the oxide semiconductor, it is preferable that theimpurity concentration in an adjacent film be also reduced. Examples ofimpurities include hydrogen, nitrogen, an alkali metal, an alkalineearth metal, iron, nickel, and silicon.

<Impurity>

Here, the influence of each impurity in the oxide semiconductor isdescribed.

When silicon or carbon, which is one of Group 14 elements, is containedin the oxide semiconductor, defect states are formed in the oxidesemiconductor. Thus, the concentration of silicon or carbon in the oxidesemiconductor and the concentration of silicon or carbon in the vicinityof an interface with the oxide semiconductor (the concentration obtainedby secondary ion mass spectrometry (SIMS)) are each set lower than orequal to 2×10¹⁸ atoms/cm³, preferably lower than or equal to 2×10¹⁷atoms/cm³.

When the oxide semiconductor contains an alkali metal or an alkalineearth metal, defect states are formed and carriers are generated in somecases. Thus, a transistor using an oxide semiconductor that contains analkali metal or an alkaline earth metal is likely to have normally-oncharacteristics. Thus, the concentration of an alkali metal or analkaline earth metal in the oxide semiconductor, which is obtained bySIMS, is set lower than or equal to 1×10¹⁸ atoms/cm³, preferably lowerthan or equal to 2×10¹⁶ atoms/cm³.

Furthermore, when the oxide semiconductor contains nitrogen, the oxidesemiconductor easily becomes n-type by generation of electrons servingas carriers and an increase in carrier concentration. As a result, atransistor using an oxide semiconductor containing nitrogen as asemiconductor is likely to have normally-on characteristics. Whennitrogen is contained in the oxide semiconductor, trap states aresometimes formed. This might make the electrical characteristics of thetransistor unstable. Therefore, the concentration of nitrogen in theoxide semiconductor, which is obtained by SIMS, is set lower than 5×10¹⁹atoms/cm³, preferably lower than or equal to 5×10¹⁸ atoms/cm³, furtherpreferably lower than or equal to 1×10¹⁸ atoms/cm³, still furtherpreferably lower than or equal to 5×10¹⁷ atoms/cm³.

Hydrogen contained in the oxide semiconductor reacts with oxygen bondedto a metal atom to be water, and thus forms an oxygen vacancy in somecases. Entry of hydrogen into the oxygen vacancy generates an electronserving as a carrier in some cases. Furthermore, bonding of part ofhydrogen to oxygen bonded to a metal atom causes generation of anelectron serving as a carrier in some cases. Thus, a transistor using anoxide semiconductor containing hydrogen is likely to have normally-oncharacteristics. Accordingly, hydrogen in the oxide semiconductor ispreferably reduced as much as possible. Specifically, the hydrogenconcentration in the oxide semiconductor, which is obtained by SIMS, isset lower than 1×10²⁰ atoms/cm³, preferably lower than 1×10¹⁹ atoms/cm³,further preferably lower than 5×10¹⁸ atoms/cm³, still further preferablylower than 1×10¹⁸ atoms/cm³.

When an oxide semiconductor with sufficiently reduced impurities is usedfor the channel formation region of the transistor, stable electricalcharacteristics can be given.

This embodiment can be combined with the other embodiments asappropriate.

Embodiment 4

In this embodiment, electronic devices of embodiments of the presentinvention are described with reference to FIG. 21 to FIG. 23 .

An electronic device of one embodiment of the present invention canperform image capturing or detect a touch motion in a display portion.Thus, the electronic device can have improved functionality andconvenience, for example.

Examples of the electronic devices of embodiments of the presentinvention include a digital camera, a digital video camera, a digitalphoto frame, a mobile phone, a portable game console, a portableinformation terminal, and an audio reproducing device, in addition toelectronic devices with a relatively large screen, such as a televisiondevice, a desktop or laptop personal computer, a monitor of a computeror the like, digital signage, and a large game machine such as apachinko machine.

The electronic device of one embodiment of the present invention mayinclude a sensor (a sensor having a function of measuring force,displacement, position, speed, acceleration, angular velocity,rotational frequency, distance, light, liquid, magnetism, temperature, achemical substance, sound, time, hardness, electric field, current,voltage, electric power, radiation, flow rate, humidity, gradient,oscillation, a smell, or infrared rays).

The electronic device of one embodiment of the present invention canhave a variety of functions. For example, the electronic device can havea function of displaying a variety of data (a still image, a movingimage, a text image, and the like) on the display portion, a touch panelfunction, a function of displaying a calendar, date, time, and the like,a function of executing a variety of software (programs), a wirelesscommunication function, and a function of reading out a program or datastored in a recording medium.

An electronic device 6500 illustrated in FIG. 21A is a portableinformation terminal that can be used as a smartphone.

The electronic device 6500 includes a housing 6501, a display portion6502, a power button 6503, buttons 6504, a speaker 6505, a microphone6506, a camera 6507, a light source 6508, and the like. The displayportion 6502 has a touch panel function.

The display device described in Embodiment 2 can be used in the displayportion 6502.

FIG. 21B is a schematic cross-sectional view including an end portion ofthe housing 6501 on the microphone 6506 side.

A protection member 6510 having a light-transmitting property isprovided on a display surface side of the housing 6501, and a displaypanel 6511, an optical member 6512, a touch sensor panel 6513, a printedcircuit board 6517, a battery 6518, and the like are provided in a spacesurrounded by the housing 6501 and the protection member 6510.

The display panel 6511, the optical member 6512, and the touch sensorpanel 6513 are fixed to the protection member 6510 with an adhesivelayer (not illustrated).

Part of the display panel 6511 is folded back in a region outside thedisplay portion 6502, and an FPC 6515 is connected to the part that isfolded back. An IC 6516 is mounted on the FPC 6515. The FPC 6515 isconnected to a terminal provided on the printed circuit board 6517.

A flexible display of one embodiment of the present invention can beused as the display panel 6511. Thus, an extremely lightweightelectronic device can be provided. Since the display panel 6511 isextremely thin, the battery 6518 with high capacity can be mounted withthe thickness of the electronic device controlled. An electronic devicewith a narrow frame can be obtained when part of the display panel 6511is folded back so that the portion connected to the FPC 6515 ispositioned on the rear side of a pixel portion.

Using the display device described in Embodiment 2 as the display panel6511 allows image capturing on the display portion 6502. For example, animage of a fingerprint is captured by the display panel 6511; thus,fingerprint authentication can be performed.

By further including the touch sensor panel 6513, the display portion6502 can have a touch panel function. A variety of types such as acapacitive type, a resistive type, a surface acoustic wave type, aninfrared type, an optical type, and a pressure-sensitive type can beused for the touch sensor panel 6513. Alternatively, the display panel6511 may function as a touch sensor; in such a case, the touch sensorpanel 6513 is not necessarily provided.

FIG. 22A illustrates an example of a television device. In a televisiondevice 7100, a display portion 7000 is incorporated in a housing 7101.Here, a structure in which the housing 7101 is supported by a stand 7103is illustrated.

The display device described in Embodiment 2 can be used in the displayportion 7000.

Operation of the television device 7100 illustrated in FIG. 22A can beperformed with an operation switch provided in the housing 7101 or aseparate remote controller 7111. Alternatively, the display portion 7000may include a touch sensor, and the television device 7100 may beoperated by touch on the display portion 7000 with a finger or the like.The remote controller 7111 may be provided with a display portion fordisplaying data output from the remote controller 7111. With operationkeys or a touch panel provided in the remote controller 7111, channelsand volume can be controlled and videos displayed on the display portion7000 can be controlled.

Note that the television device 7100 has a structure in which areceiver, a modem, and the like are provided. A general televisionbroadcast can be received with the receiver. When the television deviceis connected to a communication network with or without wires via themodem, one-way (from a transmitter to a receiver) or two-way (between atransmitter and a receiver or between receivers, for example) datacommunication can be performed.

FIG. 22B illustrates an example of a laptop personal computer. A laptoppersonal computer 7200 includes a housing 7211, a keyboard 7212, apointing device 7213, an external connection port 7214, and the like. Inthe housing 7211, the display portion 7000 is incorporated.

The display device described in Embodiment 2 can be used in the displayportion 7000.

FIG. 22C and FIG. 22D illustrate examples of digital signage.

Digital signage 7300 illustrated in FIG. 22C includes a housing 7301,the display portion 7000, a speaker 7303, and the like. Furthermore, thedigital signage 7300 can include an LED lamp, an operation key(including a power switch or an operation switch), a connectionterminal, a variety of sensors, a microphone, and the like.

FIG. 22D is digital signage 7400 attached to a cylindrical pillar 7401.The digital signage 7400 includes the display portion 7000 providedalong a curved surface of the pillar 7401.

A larger area of the display portion 7000 can increase the amount ofdata that can be provided at a time. The larger display portion 7000attracts more attention, so that the effectiveness of the advertisementcan be increased, for example.

The use of a touch panel in the display portion 7000 is preferablebecause in addition to display of a still image or a moving image on thedisplay portion 7000, intuitive operation by a user is possible.Moreover, for an application for providing information such as routeinformation or traffic information, usability can be enhanced byintuitive operation.

As illustrated in FIG. 22C and FIG. 22D, it is preferable that thedigital signage 7300 or the digital signage 7400 can work with aninformation terminal 7311 or an information terminal 7411 such as auser's smartphone through wireless communication. For example,information of an advertisement displayed on the display portion 7000can be displayed on a screen of the information terminal 7311 or theinformation terminal 7411. By operation of the information terminal 7311or the information terminal 7411, display on the display portion 7000can be switched.

The display device described in Embodiment 2 can be used for the displayportion of the information terminal 7311 in FIG. 22C or the informationterminal 7411 in FIG. 22D.

It is possible to make the digital signage 7300 or the digital signage7400 execute a game with the use of the screen of the informationterminal 7311 or the information terminal 7411 as an operation means(controller). Thus, an unspecified number of users can join in and enjoythe game concurrently.

Electronic devices illustrated in FIG. 23A to FIG. 23F include a housing9000, a display portion 9001, a speaker 9003, an operation key 9005(including a power switch or an operation switch), a connection terminal9006, a sensor 9007 (a sensor having a function of measuring force,displacement, position, speed, acceleration, angular velocity,rotational frequency, distance, light, liquid, magnetism, temperature, achemical substance, sound, time, hardness, electric field, current,voltage, electric power, radiation, flow rate, humidity, gradient,oscillation, a smell, or infrared rays), a microphone 9008, and thelike.

The electronic devices illustrated in FIG. 23A to FIG. 23F have avariety of functions. For example, the electronic devices can have afunction of displaying a variety of data (a still image, a moving image,a text image, and the like) on the display portion, a touch panelfunction, a function of displaying a calendar, date, time, and the like,a function of controlling processing with the use of a variety ofsoftware (programs), a wireless communication function, and a functionof reading out and processing a program or data stored in a recordingmedium. Note that the functions of the electronic devices are notlimited thereto, and the electronic devices can have a variety offunctions. The electronic devices may each include a plurality ofdisplay portions. The electronic devices may each include a camera orthe like and have a function of taking a still image or a moving imageand storing the taken image in a recording medium (an external recordingmedium or a recording medium incorporated in the camera), a function ofdisplaying the taken image on the display portion, or the like.

The details of the electronic devices illustrated in FIG. 23A to FIG.23F are described below.

FIG. 23A is a perspective view illustrating a portable informationterminal 9101. For example, the portable information terminal 9101 canbe used as a smartphone. Note that the portable information terminal9101 may be provided with the speaker 9003, the connection terminal9006, the sensor 9007, or the like. The portable information terminal9101 can display characters and image data on its plurality of surfaces.FIG. 23A illustrates an example where three icons 9050 are displayed.Information 9051 indicated by dashed rectangles can be displayed onanother surface of the display portion 9001. Examples of the information9051 include notification of reception of an e-mail, SNS, or an incomingcall, the title and sender of an e-mail, SNS, or the like, the date, thetime, remaining battery, and the reception strength of an antenna.Alternatively, the icon 9050 or the like may be displayed in theposition where the information 9051 is displayed.

FIG. 23B is a perspective view illustrating a portable informationterminal 9102. The portable information terminal 9102 has a function ofdisplaying information on three or more surfaces of the display portion9001. Here, an example in which information 9052, information 9053, andinformation 9054 are displayed on different surfaces is illustrated. Forexample, a user can check the information 9053 displayed in a positionthat can be observed from above the portable information terminal 9102,with the portable information terminal 9102 put in a breast pocket ofhis/her clothes. The user can see the display without taking out theportable information terminal 9102 from the pocket and decide whether toanswer the call, for example.

FIG. 23C is a perspective view illustrating a watch-type portableinformation terminal 9200. For example, the portable informationterminal 9200 can be used as a smartwatch. The display surface of thedisplay portion 9001 is curved and provided, and display can beperformed along the curved display surface. Mutual communication betweenthe portable information terminal 9200 and, for example, a headsetcapable of wireless communication enables hands-free calling. With theconnection terminal 9006, the portable information terminal 9200 canperform mutual data transmission with another information terminal andcharging. Note that the charging operation may be performed by wirelesspower feeding.

FIG. 23D to FIG. 23F are perspective views illustrating a foldableportable information terminal 9201. FIG. 23D is a perspective view of anopened state of the portable information terminal 9201, FIG. 23F is aperspective view of a folded state thereof, and FIG. 23E is aperspective view of a state in the middle of change from one of FIG. 23Dand FIG. 23F to the other. The portable information terminal 9201 ishighly portable in the folded state and is highly browsable in theopened state because of a seamless large display region. The displayportion 9001 of the portable information terminal 9201 is supported bythree housings 9000 joined by hinges 9055. For example, the displayportion 9001 can be folded with a radius of curvature greater than orequal to 0.1 mm and less than or equal to 150 mm.

This embodiment can be combined with the other embodiments asappropriate.

REFERENCE NUMERALS

-   -   EL: light-emitting element, MS: wiring, PD: light-receiving        element, RES: wiring, SE: wiring, TX: wiring, VG: wiring, VS:        wiring, 10A: electronic device, 10: electronic device, 11:        control portion, 12: memory portion, 13: display portion, 14:        detection portion, 21: finger, 22X: fingerprint, 22:        fingerprint, 23: fingerprint data, 24: finger, 25: fingerprint,        26: fingerprint data, 30: electronic device, 31: display        portion, 32: icon, 33: data, 34: data, 35: first data, 36:        second data, 40: electronic device, 41: display portion, 42:        input portion, 43: input key, 44: housing, 45: housing, 46:        hinge portion, 100A: display device, 100B: display device, 100C:        display device, 100D: display device, 100E: display device, 110:        light-receiving element, 112: common layer, 114: common layer,        115: common electrode, 116: protective layer, 121B: light, 121G:        light, 121R: light, 121: visible light, 122: light, 123 a: stray        light, 123 b: stray light, 123: light, 124: reflected light,        131: transistor, 132: transistor, 142: adhesive layer, 151:        substrate, 152: substrate, 153: substrate, 154: substrate, 155:        adhesive layer, 156: adhesive layer, 157: insulating layer, 158:        light shielding layer, 159 p: opening, 159: resin layer, 162:        display portion, 164: circuit, 165: wiring, 166: conductive        layer, 167: conductive layer, 169: conductive layer, 172: FPC,        173: IC, 182: buffer layer, 183: active layer, 184: buffer        layer, 190B: light-emitting element, 190G: light-emitting        element, 190R: light-emitting element, 190: light-emitting        element, 191: pixel electrode, 192B: buffer layer, 192G: buffer        layer, 192R: buffer layer, 192: buffer layer, 193B:        light-emitting layer, 193G: light-emitting layer, 193R:        light-emitting layer, 193: light-emitting layer, 194B: buffer        layer, 194G: buffer layer, 194R: buffer layer, 194: buffer        layer, 200A: display device, 200B: display device, 201:        substrate, 202: finger, 203: layer including light-receiving        element, 204: layer including light-emitting and light-receiving        element, 205: functional layer, 207: layer including        light-emitting element, 208: stylus, 209: substrate, 211:        insulating layer, 212: insulating layer, 213: insulating layer,        214 a: insulating layer, 214 b: insulating layer, 214:        insulating layer, 215: insulating layer, 216: partition, 219 a:        light shielding layer, 219 b: spacer, 221: conductive layer, 222        a: conductive layer, 222 b: conductive layer, 223: conductive        layer, 225: insulating layer, 228: region, 231 i: channel        formation region, 231 n: low-resistance region, 231:        semiconductor layer, 240: transistor, 241: transistor, 242:        connection layer, 243: transistor, 244: connection layer, 245:        transistor, 246: transistor, 247: transistor, 248: transistor,        249: transistor, 252: transistor, 261: contact portion, 262:        fingerprint, 266: path, 270B: light-emitting element, 270G:        light-emitting element, 270PD: light-receiving element, 270R:        light-emitting element, 271: pixel electrode, 273: active layer,        275: common electrode, 280A: display device, 280B: display        device, 280C: display device, 281: hole-injection layer, 282:        hole-transport layer, 283B: light-emitting layer, 283G:        light-emitting layer, 283R: light-emitting layer, 283:        light-emitting layer, 284: electron-transport layer, 285:        electron-injection layer, 6500: electronic device, 6501:        housing, 6502: display portion, 6503: power button, 6504:        button, 6505: speaker, 6506: microphone, 6507: camera, 6508:        light source, 6510: protection member, 6511: display panel,        6512: optical member, 6513: touch sensor panel, 6515: FPC, 6516:        IC, 6517: printed circuit board, 6518: battery, 7000: display        portion, 7100: television device, 7101: housing, 7103: stand,        7111: remote controller, 7200: laptop personal computer, 7211:        housing, 7212: keyboard, 7213: pointing device, 7214: external        connection port, 7300: digital signage, 7301: housing, 7303:        speaker, 7311: information terminal, 7400: digital signage,        7401: pillar, 7411: information terminal, 9000: housing, 9001:        display portion, 9003: speaker, 9005: operation key, 9006:        connection terminal, 9007: sensor, 9008: microphone, 9050: icon,        9051: information, 9052: information, 9053: information, 9054:        information, 9055: hinge, 9101: portable information terminal,        9102: portable information terminal, 9200: portable information        terminal, 9201: portable information terminal.

1. An electronic device comprising: a control portion; a memory portion;and a display portion comprising a plurality of pixels, each of theplurality of pixels comprising a light-emitting element and one of alight-receiving element and a light-emitting and light-receivingelement, wherein the display portion is configured to display a firsticon and obtain first fingerprint data in a display region of the firsticon, wherein the memory portion is configured to retain secondfingerprint data, and wherein the control portion is configured tocompare the first fingerprint data with the second fingerprint data;execute first processing associated with the first icon in the casewhere the first fingerprint data and the second fingerprint data match;and execute second processing in the case where the first fingerprintdata and the second fingerprint data do not match.
 2. The electronicdevice according to claim 1, wherein the display portion is configuredto detect a touch motion in the display region of the first icon.
 3. Theelectronic device according to claim 1, wherein the display portion isconfigured to display a second icon and obtain third fingerprint data ina display region of the second icon, wherein the memory portion isconfigured to retain fourth fingerprint data, and wherein the controlportion is configured to compare the third fingerprint data with thefourth fingerprint data; execute third processing associated with thesecond icon in the case where the third fingerprint data and the fourthfingerprint data match; and execute fourth processing in the case wherethe third fingerprint data and the fourth fingerprint data do not match.4. The electronic device according to claim 2, wherein the displayportion is configured to display a second icon and detect a touch motionin a display region of the second icon, and wherein the control portionis configured to execute third processing associated with the secondicon in the case where the display portion detects a touch motion on thesecond icon.
 5. An electronic device comprising: a control portion; amemory portion; and a display portion comprising a plurality of pixels,each of the plurality of pixels comprising a light-emitting element andone of a light-receiving element and a light-emitting andlight-receiving element, wherein the display portion is configured todisplay a first icon and obtain of first fingerprint data in a displayregion of the first icon, wherein the memory portion is configured toretain second fingerprint data, wherein the control portion isconfigured to compare each of the first fingerprint data with the secondfingerprint data; execute first processing associated with the firsticon in the case where each of the first fingerprint data matches withany of the second fingerprint data; and execute second processing in thecase where at least one of the first fingerprint data does not matchwith any of the second fingerprint data.
 6. The electronic deviceaccording to claim 1, wherein the second processing is processing tolock data associated with the first icon.
 7. The electronic deviceaccording to claim 1, wherein the first processing is processing todisplay data associated with the first icon on the display portion, andwherein the second processing is processing to display data differentfrom the data associated with the first icon on the display portion. 8.The electronic device according to claim 5, wherein the secondprocessing is processing to lock data associated with the first icon. 9.The electronic device according to claim 5, wherein the first processingis processing to display data associated with the first icon on thedisplay portion, and wherein the second processing is processing todisplay data different from the data associated with the first icon onthe display portion.
 10. The electronic device according to claim 1,wherein the display portion is configured to obtain the firstfingerprint data of a plurality of users in the display regionconcurrently, and wherein the second fingerprint data comprisesfingerprint data of users registered in advance.
 11. The electronicdevice according to claim 5, wherein the display portion is configuredto obtain the first fingerprint data of a plurality of users in thedisplay region concurrently, and wherein the second fingerprint datacomprises fingerprint data of users registered in advance.